Jed Buchwald: Isaac Newton and the Philosophy of Science
音乐与艺术物理与宇宙学生物与进化技术与编程历史与文明
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🔑 关键词
newtondonsciencewaysgoingsaidcoursecertaintheorylightcalledputaragoyoungphysicsdidnstuffnaturehookeable
💬 精彩语录
"If we look at the long arc of history of science, from back when we were in the caves trying to knock"
如果我们回顾一下科学史的长弧，从我们在洞穴里试图敲击的时候开始
— Jed Buchwald （12:41.120）
"everything and its history and comment on what the heck does that even mean, the theory of everything."
一切及其历史，并评论这到底意味着什么，万物理论。
— Jed Buchwald （17:37.440）
"and have assumed for a long time, I'll come back to when in a moment, that if I take a little device,"
很长一段时间以来我一直假设，过一会儿我就会回想起，如果我拿一个小装置，
— Jed Buchwald （18:17.680）
"worked out well, like that competition is good for the progress of science? Yeah, it almost always is"
效果很好，就像竞争有利于科学进步一样？是的，几乎总是如此
— Jed Buchwald （1:11:10.240）
"to be nasty, although sometimes it is. So for the example with optics, could you comment on that one?"
令人讨厌，尽管有时确实如此。那么对于光学的例子，您能对此发表评论吗？
— Jed Buchwald （1:11:21.520）
🎙️ 完整对话（964 条）
Lex Fridman (00:00.000)
The following is a conversation with Jed Buchwald, a professor of history and a philosopher of
以下是与历史学教授、哲学家杰德·布赫瓦尔德 (Jed Buchwald) 的对话
Lex Fridman (00:05.840)
science at Caltech, interested especially in the development of scientific concepts
加州理工学院的科学专业，对科学概念的发展特别感兴趣
Lex Fridman (00:12.000)
and the instruments used to create and explore new effects and ideas in science.
以及用于创造和探索科学新效果和新想法的仪器。
Lex Fridman (00:19.440)
To support this podcast, please check out our sponsors in the description.
为了支持这个播客，请在说明中查看我们的赞助商。
Lex Fridman (00:23.200)
This is the Lex Friedman Podcast, and here is my conversation with Jed Buchwald.
这是莱克斯·弗里德曼播客，这是我与杰德·布赫瓦尔德的对话。
Jed Buchwald (00:31.600)
Does science progress via paradigm shifts and revolutions as philosopher Thomas Kuhn said,
正如哲学家托马斯·库恩所说，科学的进步是通过范式转变和革命来实现的吗？
Lex Fridman (00:38.160)
or does it progress gradually? What do you think?
还是逐渐进展？你怎么认为？
Jed Buchwald (00:41.280)
Well, I got into this field because I was Tom Kuhn's research assistant 50 years ago, 52 years
嗯，我进入这个领域是因为 50 年前、52 年前我是 Tom Kuhn 的研究助理
Jed Buchwald (00:48.240)
ago. He pulled me into it out of physics instead. So I know his work pretty well. And in the years
前。相反，他把我从物理领域拉了进去。所以我对他的工作非常了解。而在这些年里
Jed Buchwald (00:55.600)
when I was at MIT running an institute, he was then in the philosophy department, used to come
当我在麻省理工学院管理一个研究所时，他当时在哲学系，过去常常来
Jed Buchwald (01:01.040)
over all the time to the talks we held and so on. So what would I say about that? He, of course,
一直到我们举行的会谈等等。那么对此我该怎么说呢？他，当然，
Jed Buchwald (01:08.160)
developed his ideas a lot over the years. The thing that he's famous for, the structure of
多年来他的想法得到了很大的发展。他出名的事情，结构
Jed Buchwald (01:14.800)
scientific revolutions came out in 62. And as you just said, it offered an outline for what he
科学革命出现于 62 年。正如你刚才所说，它为他的研究提供了一个纲要。
Jed Buchwald (01:24.720)
called a paradigmatic structure, namely the notion that you have to look at what scientists do as
称为范式结构，即你必须将科学家所做的事情视为
Jed Buchwald (01:31.280)
forming a community of investigators, and that they're trying to solve various puzzles, as he
组建了一个调查员社区，他们正在尝试解决各种难题，正如他所言
Jed Buchwald (01:38.800)
would put it, that crop up, figuring out how this works, how that works and so on. And of course,
会说，突然出现，弄清楚它是如何工作的，它是如何工作的等等。当然，
Jed Buchwald (01:44.800)
they don't do it out of the blue. They do it within a certain framework. The framework can
他们不会突然这样做。他们是在一定的框架内进行的。该框架可以
Jed Buchwald (01:49.760)
be pretty vague. He called it a paradigm. And his notion was that eventually they run into troubles
非常模糊。他称之为范式。他的想法是他们最终会遇到麻烦
Jed Buchwald (01:57.200)
or what he called anomalies. That kind of cracks things. Somebody new comes along with a different
或者他所说的异常现象。那种东西会破裂。新人带着不同的到来
Jed Buchwald (02:03.680)
way of doing it, etc. Do I think things work that way? No, not really. Tom and I used to have
我认为事情是这样进行的吗？不，不是真的。汤姆和我曾经有过
Jed Buchwald (02:11.040)
lengthy discussions about that over the years. I do think there is a common structure that
Jed Buchwald (02:20.000)
formulates both theoretical and experimental practices. And historians nowadays of science
Jed Buchwald (02:26.240)
like to refer to scientific work as what scientists practice. It's almost craftsman like.
Jed Buchwald (02:34.960)
They can usually adapt in various ways. And I can give you all kinds of examples of that.
Jed Buchwald (02:41.840)
I once wrote a book on the origins of wave theory of light. And that is one of the paradigmatic
Jed Buchwald (02:49.200)
examples that Tom used. Only it didn't work that way exactly because he thought that what happened
Jed Buchwald (02:56.960)
was that the wave theory ran into trouble with a certain phenomenon, which it couldn't crack.
Jed Buchwald (03:05.680)
Well, it turned out that in fact, historically that phenomenon was actually not relevant
Jed Buchwald (03:13.520)
later on to the wave theory. And when the wave theory came in, the alternative to it,
Jed Buchwald (03:19.760)
which had prevailed, which was Newton's views light as particles that it seemed couldn't
Jed Buchwald (03:25.760)
explain what the wave theory could explain. Again, not true. Not true. Much more complex
Jed Buchwald (03:33.200)
than that. The wave theory offered the opportunity to deploy novel experimental and mathematical
Jed Buchwald (03:40.640)
structures, which gave younger scientists, mathematicians and others, the opportunity
Jed Buchwald (03:47.520)
to effect, manufacture, make new sorts of devices. It's not that the alternative couldn't sort of
Jed Buchwald (03:56.480)
explain these things, but it never was able to generate them de novo as novelties. In other
Jed Buchwald (04:04.160)
words, if you think of it as something scientists want to progress in the sense of finding new stuff
Jed Buchwald (04:10.640)
to solve, then I think what often happens is that it's not so much that the prevailing view
Jed Buchwald (04:17.200)
can't crack something as that it doesn't give you the opportunity to do new stuff.
Lex Fridman (04:23.120)
When you say new stuff, are we referring to experimental science here or
Lex Fridman (04:27.280)
new stuff in the space of new theories?
Lex Fridman (04:29.680)
Could be both. Could be both actually.
Lex Fridman (04:32.800)
So how does that... Can you maybe elaborate a little bit on the story of the wave view?
Jed Buchwald (04:36.720)
Sure. The prevailing view of light, at least in France where the wave theory really first took
Jed Buchwald (04:43.840)
off, although it had been introduced in England by Thomas Young, the prevailing theory dates back
Jed Buchwald (04:49.040)
to Newton that light is a stream of particles and that refraction and reflection involve sort
Jed Buchwald (04:55.520)
of repulsive and attractive forces that deflect and bend the paths of these particles. Newton was
Jed Buchwald (05:03.680)
not able successfully to deal with the phenomenon of what happens when light goes past a knife's
Jed Buchwald (05:10.560)
edge or a sharp edge, what we now call diffraction. He had cooked up something about it that no
Jed Buchwald (05:19.120)
mathematical structure could be applied. Thomas Young first, but really this guy named Augustin
Jed Buchwald (05:26.080)
Fresnel in France deployed, in Fresnel's case, rather advanced calculus forms of mathematics,
Lex Fridman (05:35.840)
which enabled computations to be done and observations to be melded with these
Jed Buchwald (05:41.840)
computations in a way that you could not do or see how to do with Newton. Did that mean that the
Jed Buchwald (05:49.120)
Newtonian explanation of what goes on in diffraction fails? Not really. You can actually
Jed Buchwald (05:58.000)
make it work, but you can't generate anything new out of it. Whereas using the mathematics
Jed Buchwald (06:05.280)
of wave optics in respect to a particular phenomenon called polarization, which ironically
Jed Buchwald (06:12.560)
was discovered by partisans of Newton's way of doing things, you were able to generate devices
Jed Buchwald (06:20.240)
which reflect light in crystals, do various things that the Newtonian way could accommodate only
Jed Buchwald (06:29.120)
after the fact. They couldn't generate it from the beginning. And so if you want to be somebody who
Jed Buchwald (06:36.480)
is working a novel vein, which increasingly becomes the case with people who become what we
Jed Buchwald (06:44.720)
now call physicists in the 1820s, 30s, and 40s in particular, then that's the direction you're going
Jed Buchwald (06:51.120)
to go. But there were holdouts until the 1850s. I want to try to elaborate on the nature of the
Jed Buchwald (06:57.360)
disagreement you have with Thomas Kuhn. So do you still believe in paradigm shifts? Do you still see
Jed Buchwald (07:02.800)
that there's ideas that really have a transformational effect on science? The nature of
Jed Buchwald (07:09.680)
the disagreement has to do with how those paradigm shifts come to be? How they come to be and how
Jed Buchwald (07:16.880)
they change. I certainly think they exist. How strong they may be at any given time is maybe not
Jed Buchwald (07:25.280)
quite as powerful as Tom thought in general. Although towards the end of his life, he was
Jed Buchwald (07:31.200)
beginning to develop different modifications of his original way of thinking. But I don't think
Jed Buchwald (07:38.720)
that the changes happened quite so neatly, if you will, in reaction to novel experimental
Jed Buchwald (07:47.840)
observations. They get much more complex than that. In terms of neatness, how much of science
Jed Buchwald (07:56.880)
progresses by individual lone geniuses and how much by the messy collaboration of competing and
Jed Buchwald (08:05.360)
cooperating humans? I don't think you can cut that with a knife to say it's this percent and
Jed Buchwald (08:18.400)
that percent. It's almost always the case that there are one or two or maybe three individuals
Jed Buchwald (08:27.680)
who are sort of central to what goes on when things begin to shift. Are they inevitably and
Jed Buchwald (08:37.840)
solely responsible for what then begins to happen in a major way? I think not. It depends. You can
Jed Buchwald (08:48.080)
go very far back with this, even into antiquity to see what goes on. The major locus we always
Jed Buchwald (08:59.200)
talk about from the beginning is if you're talking about Galileo's work on motion, for example,
Jed Buchwald (09:05.680)
were there ways of accommodating it that others could adapt to without buying into the whole
Jed Buchwald (09:11.760)
scheme? Yes. Did it eventually evolve and start convincing people because you could also do
Jed Buchwald (09:19.600)
other things with it that you couldn't otherwise do? Also, yes. Let me give you an example.
Jed Buchwald (09:26.160)
The great French mathematician philosopher Descartes, who was a mechanical philosopher,
Jed Buchwald (09:32.720)
he believed the world was matter in motion. He never thought much of what Galileo had done
Jed Buchwald (09:38.880)
in respect to motion because he thought, well, at best, it's some sort of approximative scheme
Jed Buchwald (09:44.000)
or something like that. But one of his initial, I wouldn't call him a disciple, but follower,
Jed Buchwald (09:51.600)
who then broke with him in a number of ways, was a man named Christian Huygens, who was,
Jed Buchwald (09:56.960)
along with Newton, one of the two greatest scientists of the 17th century. Huygens is
Jed Buchwald (10:02.640)
older than Newton, and Huygens nicely deployed Galilean relationships in respect to motion
Lex Fridman (10:11.440)
to develop all sorts of things, including the first pendulum governed clock,
Lex Fridman (10:19.280)
and even figured out how to build one, which keeps perfect time, except it didn't work. But
Lex Fridman (10:24.720)
he had the mathematical structure for it. How well known is Huygens?
Lex Fridman (10:28.400)
Oh, very well known. Should I know him well?
Lex Fridman (10:31.040)
Yes, you should. Interesting.
Jed Buchwald (10:33.280)
You should definitely know him.
Lex Fridman (10:34.560)
No, no, no, no, no. Can we define should here?
Jed Buchwald (10:37.760)
Okay.
Lex Fridman (10:38.240)
Because I don't.
Jed Buchwald (10:39.600)
Right.
Lex Fridman (10:40.880)
So is this should like, yeah, can you define should?
Jed Buchwald (10:48.640)
Should means this. If you had taken up to a second year physics courses, you should,
Jed Buchwald (10:55.360)
you would have heard his name because one of the fundamental principles in optics is called
Jed Buchwald (11:00.640)
Huygens principle.
Lex Fridman (11:03.280)
Okay.
Jed Buchwald (11:03.680)
Okay.
Lex Fridman (11:04.320)
Yeah, so I have and I have heard his name.
Jed Buchwald (11:07.040)
There you go.
Lex Fridman (11:07.920)
No, but I don't remember.
Lex Fridman (11:08.800)
But you don't remember.
Lex Fridman (11:09.760)
So I mean, there's a very different thing between names attached to principles and laws and so on
Jed Buchwald (11:16.640)
that you sometimes let go of, you just remember the equations of the principles themselves,
Lex Fridman (11:21.520)
and the personalities of science. And there's certain personalities,
Jed Buchwald (11:25.760)
certain human beings that stand out. And that's why there's a sense to which the lone inventor,
Jed Buchwald (11:32.880)
the lone scientist is the way I personally mean, I think a lot of people think about the history
Jed Buchwald (11:38.880)
of science is these lone geniuses. Without them, the senses, if you remove Newton from the picture,
Jed Buchwald (11:45.760)
if you remove Galileo from the picture, then science would, there's almost a feeling like
Jed Buchwald (11:51.520)
it would just have stopped there. Or at the very least, there's a feeling like it would take much
Lex Fridman (11:57.360)
longer to develop the things that were developed. Is that a silly way to look at the history?
Jed Buchwald (12:01.840)
That's not entirely incorrect, I suppose. I find it difficult to believe that had Galileo not
Jed Buchwald (12:12.800)
existed, that eventually someone like Huygens, for instance, given the context of the time,
Lex Fridman (12:19.680)
what was floating around in the belief structure concerning the nature of the world and so on,
Jed Buchwald (12:27.440)
the developments in mathematics and whatnot, that sooner or later, whether it would have been
Jed Buchwald (12:34.560)
exactly the same or not, I cannot say. But would things have evolved? Yes.
Jed Buchwald (12:41.120)
If we look at the long arc of history of science, from back when we were in the caves trying to knock
Jed Buchwald (12:54.080)
two rocks together, or maybe make a basic tool to a long time from now, many centuries from now,
Jed Buchwald (13:03.040)
when human civilization finally destroys itself. If we look at that history, and imagine you're
Jed Buchwald (13:09.680)
a historian at the end, like with the fire of the apocalypse coming upon us, and you look back at
Jed Buchwald (13:16.800)
this time in the 21st century, how far along are we on that arc? Do you sense? Have we invented
Lex Fridman (13:26.000)
and discovered everything that's to be discovered, or are we at like below 1%? You're going to get a
Jed Buchwald (13:33.440)
lot of absurd questions today. I apologize. It's a lugubrious picture you're painting there.
Jed Buchwald (13:39.920)
I don't even know what the word lugubrious means, but I love it. Lugubrious.
Jed Buchwald (13:44.560)
Well, let me try and separate the question of whether we're all going to die in an apocalypse
Jed Buchwald (13:51.200)
in several hundred years or not from the question of where science may be sitting.
Jed Buchwald (13:57.680)
Take that as an assumption. Okay. I find that hard to say. And I find it hard to say
Jed Buchwald (14:07.760)
because in the deepest sense of the term, as it's usually deployed by philosophers of science today,
Jed Buchwald (14:17.280)
I'm not fundamentally a realist. That is to say, I think our access to the inner workings of nature
Jed Buchwald (14:30.080)
is inevitably mediated by what we can do with the materials and factors around us. We can probe
Jed Buchwald (14:40.400)
things in various ways. Does that mean that I don't think that the standard model in quantum
Jed Buchwald (14:47.200)
electrodynamics is incorrect? Of course not. I wouldn't even dream of saying such a thing.
Jed Buchwald (14:52.400)
It can do a lot, especially when it comes to figuring out what's happening in very large,
Jed Buchwald (14:59.040)
expensive particle accelerators and applying results in cosmology and so on as well.
Jed Buchwald (15:09.280)
Do I think that we have inevitably probed the depths of reality through this? I do not agree
Jed Buchwald (15:16.880)
with Steven Weinberg who thinks we have about such things. Do I, on the other hand, think that
Jed Buchwald (15:24.720)
the way in which science has been moving for the last hundred years, physics in particular is what
Jed Buchwald (15:30.640)
I have in mind, will continue on the same course? In that sense, I don't because we're not going to
Jed Buchwald (15:38.160)
be building bigger and bigger and more and more expensive machines to rip apart particles in
Jed Buchwald (15:44.560)
various ways. In which case, what are physicists going to do? They'll turn their attention to other
Jed Buchwald (15:50.640)
aspects. There are all sorts of things we've never explained about the material world.
Jed Buchwald (15:57.360)
We don't have theories that go beyond a certain point for all sorts of things.
Jed Buchwald (16:04.240)
Can we, for example, start with the standard model and work our way up all the way to chemical
Jed Buchwald (16:09.600)
transformations? You can make an argument about it and you can justify things, but in chemistry,
Jed Buchwald (16:17.200)
that's not the way people work. They work with much higher level quantum mechanical relationships
Lex Fridman (16:22.560)
and so on. This notion of the deep theory to explain everything is a longstanding belief
Lex Fridman (16:33.200)
which goes back pretty far, although I think it only takes its fullest form
Jed Buchwald (16:41.440)
sometime towards the end of the 19th century. Maybe we just speak to that. You're referring to
Jed Buchwald (16:48.640)
a hope, a dream, a reality of coming up with a theory of everything that explains everything.
Jed Buchwald (16:55.200)
There's a very specific thing that that currently means in physics,
Jed Buchwald (16:58.720)
is the unification of the laws of physics. But I'm sure in antiquity or before it meant maybe
Jed Buchwald (17:06.000)
something else, or is it always about physics? Because I mean, I think as you've kind of implied
Jed Buchwald (17:13.520)
in physics, there's a sense once you get to the theory of everything, you've understood everything,
Lex Fridman (17:17.760)
but there's a very deep sense in which you've actually understood not very much at all.
Jed Buchwald (17:21.920)
You've understood at that particular level how things work, but you don't understand how the
Jed Buchwald (17:26.880)
abstractions on top of abstractions form, all the way to the chemistry, to the human mind,
Lex Fridman (17:31.280)
and the human societies, and all those kinds of things. So maybe you can speak to the theory of
Jed Buchwald (17:37.440)
everything and its history and comment on what the heck does that even mean, the theory of everything.
Jed Buchwald (17:43.040)
Well, I don't think you can go back that far with something like that. Maybe to the, at best,
Jed Buchwald (17:48.800)
to the 17th century. If you go back all the way in antiquity, there are, of course,
Jed Buchwald (17:53.840)
discussions about the nature of the world. But first of all, you have to recognize that the
Jed Buchwald (18:07.040)
manipulative character of physics and chemistry, the probing of... Let me put it this way. We assume
Lex Fridman (18:17.680)
and have assumed for a long time, I'll come back to when in a moment, that if I take a little device,
Jed Buchwald (18:26.400)
which is really complicatedly made out of all kinds of things, and I put a piece of some material in
Jed Buchwald (18:33.360)
it, and I monkey around with it and do all kinds of unnatural things to it, things that wouldn't
Jed Buchwald (18:39.760)
happen naturally, and I find out how it behaves and whatnot, and then I try and make an argument
Jed Buchwald (18:46.880)
about how that really applies even in the natural world without any artificial structures and so on.
Jed Buchwald (18:54.240)
That's not a belief that was widely held by pretty much anyone until sometime maybe
Jed Buchwald (19:01.840)
in the 1500s. And when it was first held, it was held by people we now call alchemists.
Lex Fridman (19:08.880)
So alchemy was the first, the early days of the theory of everything, of a dream of a theory of
Jed Buchwald (19:13.360)
everything. I would put it a little differently. I think it's more along the way, a dream that
Jed Buchwald (19:20.720)
by probing nature in artificially constructed ways, we can find out what's going on deep down there.
Lex Fridman (19:32.640)
So that's distinct from science being an observing thing, where you observe nature
Lex Fridman (19:39.200)
and you study nature. You're talking about probing, like messing with nature to understand it.
Jed Buchwald (19:45.520)
Indeed I am. But that, of course, is the very essence of experimental science. You have to
Jed Buchwald (19:54.000)
manipulate nature to find out things about it, and then you have to convince others that you haven't
Jed Buchwald (1:00:03.360)
between the earth, let's say, and the moon, is contrary to fundamental beliefs held by many of
Jed Buchwald (1:00:13.520)
the mechanical philosophers, as they're called at the time, in which everything has to involve
Jed Buchwald (1:00:18.720)
at least a sequence of direct contacts, has to be something between here and there that's involved.
Lex Fridman (1:00:26.400)
And Hooke, probably not thinking terribly deeply about it, based on what he said,
Lex Fridman (1:00:33.440)
along with others, like the architect and mathematician Christopher Wren,
Jed Buchwald (1:00:37.840)
harken back to the notion that, well, maybe there is a kind of magnetic relationship between the
Jed Buchwald (1:00:44.160)
moon and maybe the planets and the earth and gravity and so on, vague, but establishing a
Jed Buchwald (1:00:49.600)
direct connection somehow, however it's happening, forget about it. Newton wouldn't have cared about
Jed Buchwald (1:00:56.240)
that, if that's all they said, but it was when Hooke mentioned this different way of thinking
Jed Buchwald (1:01:01.120)
about the motion, a way he could certainly have thought of, because it does not contradict
Jed Buchwald (1:01:05.920)
anything. Newton is a brilliant mathematician, and he could see that you could suddenly start
Jed Buchwald (1:01:13.840)
to do things with that, that you otherwise wouldn't, and this led eventually to another
Jed Buchwald (1:01:19.840)
controversy with Hooke, in which Hooke said, well, after Newton published his Great Principia,
Jed Buchwald (1:01:25.360)
I gave him how to do this. And then Newton, of course, got ticked off about that and said, well,
Lex Fridman (1:01:30.240)
listen to this, I did everything, and because he had a picayune little idea,
Jed Buchwald (1:01:34.640)
he thinks he can take credit for it. Okay. So his ability to play with his ideas mathematically is
Lex Fridman (1:01:43.040)
what solidified the initial intuition that you could have. Was that the first time he was born,
Jed Buchwald (1:01:48.000)
the idea that you have action at a distance, that you can have forces without contact,
Jed Buchwald (1:01:54.000)
which is another revolutionary idea? I would say that in the sense of dealing with
Jed Buchwald (1:02:02.000)
the mechanics of force like effects considered to act at some distance, it is novel with both
Jed Buchwald (1:02:14.160)
Hooke and Newton at the time. The notion that two things might interact at a distance with one
Jed Buchwald (1:02:21.200)
another without direct contact, that goes back to antiquity. Only there it would be thought of
Jed Buchwald (1:02:26.240)
more as a sympathetic reaction to a magnet and a piece of iron. They have a kind of mutual sympathy
Jed Buchwald (1:02:35.600)
for one another. Like what? Love? What are we talking about? Actually, they do sometimes talk
Jed Buchwald (1:02:41.520)
like that. That is love. See, now I talk like that all the time. I think love is somehow
Jed Buchwald (1:02:49.040)
in consciousness or forces of physics that yet to be discovered. Okay. Now there's the other side
Jed Buchwald (1:02:58.720)
of things, which is calculus that you began to talk about. So Newton brought a lot of things
Jed Buchwald (1:03:03.760)
to this world. One of them is calculus. What is calculus? And what was Newton's role in bringing
Jed Buchwald (1:03:13.040)
it to life? What was it like? What was the story of bringing calculus to this world? Well, since
Jed Buchwald (1:03:21.200)
the publication starting many decades ago by Tom Whiteside, who's now deceased, of Newton's
Jed Buchwald (1:03:28.000)
mathematical papers, we know a lot about how he was pushing things and how he was developing things.
Jed Buchwald (1:03:34.640)
It's a complex question to say what calculus is. Calculus is the set of mathematical techniques
Jed Buchwald (1:03:42.560)
that enable you to investigate what we now call functions, mathematical functions,
Jed Buchwald (1:03:49.840)
which are continuous. That is, that are not formed out of discrete sets like the counting numbers,
Jed Buchwald (1:03:58.800)
for instance. Newton, there were already procedures for solving problems involving
Jed Buchwald (1:04:11.520)
such things as finding areas to under curves and tangents to curves by using geometrical structures,
Lex Fridman (1:04:20.720)
but only for certain limited types of curves, if you will. Newton as a young man, we know this is
Lex Fridman (1:04:31.520)
what happened, is looking at a formula which involves an expansion in separate terms, polynomial
Jed Buchwald (1:04:42.160)
terms, as we say, for certain functions. I know I don't want to get complicated here about this,
Lex Fridman (1:04:48.880)
and he realizes it could be generalized. And he tries the generalization and that leads him to
Jed Buchwald (1:04:55.920)
an expansion formula called the binomial theorem. That enables him to move ahead with the notion
Jed Buchwald (1:05:03.840)
that if I take something that has a certain value, and I add a little bit to it, and I use
Jed Buchwald (1:05:10.960)
this binomial theorem and expand things out, I can begin to do new things. And the new things that
Jed Buchwald (1:05:17.360)
he begins to do leads him to a recognition that the calculations of areas and the calculations
Jed Buchwald (1:05:24.960)
of tangents to curves are reciprocal to one another. And the procedures that he develops
Jed Buchwald (1:05:33.920)
is a particular form of the calculus in which he considers small increments and then continuous
Jed Buchwald (1:05:43.520)
flows and changes of curves and so on. And we have relics of it in physics today, the notation
Jed Buchwald (1:05:52.560)
in which you put a dot over a variable indicating the rate of change of the variable. That's
Lex Fridman (1:05:59.360)
Newton's original type of notation. The dot. Yeah, the dot notation.
Jed Buchwald (1:06:09.920)
Possibly independently of Newton, because he didn't publish this thing, although he became
Jed Buchwald (1:06:16.560)
quite well known as quite a brilliant young man, in part because people heard about his work and
Lex Fridman (1:06:24.720)
so on. When another young man by the name of Gottfried Leibniz visited London and he heard
Jed Buchwald (1:06:34.320)
about these things, it is said that he independently develops his form of the calculus,
Jed Buchwald (1:06:42.160)
which is actually the form we use today, both in notation and perhaps in certain
Jed Buchwald (1:06:47.840)
fundamental ways of thinking. It has remained a controversial point as to where exactly and how
Jed Buchwald (1:06:56.160)
much independently Leibniz did it. Leibniz aficionados think and continue to maintain he
Jed Buchwald (1:07:02.400)
did it completely independently. Newton, when he became president of the Royal Society, put together
Jed Buchwald (1:07:08.000)
a group to go on the attack saying, no, he must have taken everything. We don't know.
Lex Fridman (1:07:14.720)
But I will tell you this. About 25 or so years ago, a scholar who's a professor at Indiana now
Jed Buchwald (1:07:23.920)
named Domenico Melli got his hands on a Leibniz manuscript called the Tentamen,
Lex Fridman (1:07:31.440)
which was Leibniz's attempt to produce an alternative to Newton's mechanics.
Jed Buchwald (1:07:36.720)
Mm hmm.
Lex Fridman (1:07:37.760)
And it comes to some conclusions that you have in Newton's mechanics. Well, he published that,
Lex Fridman (1:07:43.360)
but Melli got the manuscript. And what Melli found out was that Leibniz reverse engineered
Jed Buchwald (1:07:49.520)
the Principia and cooked it backwards so that he could get the results he wanted.
Jed Buchwald (1:07:55.520)
That was for the mechanics. So that means his mind allows for that kind of thing.
Lex Fridman (1:07:59.680)
Some people.
Jed Buchwald (1:08:00.960)
You're breaking some news today. You're starting some whole drama.
Jed Buchwald (1:08:04.320)
Some people think so. I think most historians of mathematics do not agree with that.
Jed Buchwald (1:08:09.840)
A friend of mine, rather well known physicist, unfortunately, died a couple of years ago named
Jed Buchwald (1:08:15.280)
Mike Nowenberg at UC Santa Cruz, had some evidence along those lines. Didn't pass mustard
Jed Buchwald (1:08:23.040)
with many of my friends who are historians of math. In fact, I edit with a historian of math,
Jed Buchwald (1:08:28.720)
a technical journal, and we were unable to publish it in there because we couldn't get
Jed Buchwald (1:08:33.920)
it through any of our colleagues. But I am, I remain suspicious.
Lex Fridman (1:08:41.920)
What is it about those tense relationships and that kind of drama? Einstein doesn't
Jed Buchwald (1:08:47.040)
appear to have much of that drama. Nobody claimed, I haven't heard claims that they've,
Jed Buchwald (1:08:53.360)
perhaps because it's such crazy ideas, of any of his major inventions, major ideas,
Jed Buchwald (1:09:00.640)
being those that are basically, I came up with it first or independently. There's not,
Jed Buchwald (1:09:07.360)
as far as I'm aware, not many people talk about general relativity, especially in those terms.
Lex Fridman (1:09:12.880)
But with Newton, that was the case. I mean, is that just a natural outgrowth of how science works?
Jed Buchwald (1:09:20.320)
Is there going to be personalities that, I'm not saying this about Linus, but maybe I am,
Lex Fridman (1:09:25.040)
but there's people who steal ideas for the, because of ego, because of all those kinds of things.
Jed Buchwald (1:09:35.040)
I don't think it's all that common, frankly. The Newton book, Leibniz, Contratemps and so on.
Jed Buchwald (1:09:43.040)
Well, you're at the beginnings of a lot of things there and so on. These are difficult
Lex Fridman (1:09:48.240)
and complex times as well. These are times in which science as an activity pursued by other than,
Jed Buchwald (1:09:57.920)
let us say, interested aristocrats is becoming something somewhat different. It's not
Jed Buchwald (1:10:05.440)
a professional community of investigators in the same way. It's also a period in which
Jed Buchwald (1:10:12.000)
procedures and rules or practice are being developed to avoid attacking one another directly
Lex Fridman (1:10:23.120)
and pulling out a sword to cut off the other guy's head if he disagrees with you and so on.
Lex Fridman (1:10:28.960)
So it's a very different period. Controversies happen. People get angry. I can think of a number
Jed Buchwald (1:10:35.440)
of others, including in the development of optics in the 19th century and so on, and it can get hot
Jed Buchwald (1:10:42.560)
under the collar. Sometimes one character who's worked an area extensively, whether they've come
Jed Buchwald (1:10:50.640)
up with something terribly novel or not, and somebody else kind of moves in and does completely
Jed Buchwald (1:10:57.840)
different and novel things, the first guy gets upset about it because he's sort of muscled into
Lex Fridman (1:11:03.840)
what I thought was my area. You find that sort of stuff. But do you have examples of cases where it
Jed Buchwald (1:11:10.240)
worked out well, like that competition is good for the progress of science? Yeah, it almost always is
Jed Buchwald (1:11:16.240)
good in that sense. It's just painful for the individuals involved. It can be. It doesn't have
Lex Fridman (1:11:21.520)
to be nasty, although sometimes it is. So for the example with optics, could you comment on that one?
Jed Buchwald (1:11:28.880)
Well, yeah, sure. There are several, but I could give you... All right, so I'll give you this
Jed Buchwald (1:11:36.720)
example that probably is the most pertinent. The first polytechnic school like MIT or Caltech was
Jed Buchwald (1:11:49.280)
actually founded in France during the French Revolution. It exists today. It's the Ecole
Jed Buchwald (1:11:53.760)
Polytechnique. Two people who were there were two young men in the 90s, 1790s named on the one hand
Jed Buchwald (1:12:06.160)
Francois Arago and the other Jean Baptiste Biot. They both lived a long time, well into the 1850s.
Jed Buchwald (1:12:13.600)
Arago became a major administrator of science and Biot's career started to peter out after about the
Jed Buchwald (1:12:22.160)
late teens. Now, they are sent on an expedition, which was one of the expeditions involving
Jed Buchwald (1:12:30.880)
measuring things to start the metric system. There's a lot more to that story. Anyway,
Jed Buchwald (1:12:36.320)
they come back. Arago gets separated. He's captured by pirates actually. Wounds up in
Jed Buchwald (1:12:46.560)
Tangier, escapes, is captured again. Everybody thinks he's dead. He gets back to Paris and so on.
Jed Buchwald (1:12:55.440)
He's greeted as a hero and whatnot. In the meantime, Biot has pretty much published some
Jed Buchwald (1:13:00.640)
of the stuff that he's done and Arago doesn't get much credit for it and Arago starts to get very
Jed Buchwald (1:13:05.680)
angry and Biot is known for this kind of thing. Biot starts investigating a new phenomenon in
Jed Buchwald (1:13:17.920)
optics involving something called polarization and he writes all kinds of stuff on it. Arago
Jed Buchwald (1:13:25.920)
looks into this and decides to write some things as well and actually Biot gets mostly interested
Jed Buchwald (1:13:33.040)
in it when he finds out that Arago is doing stuff. Now, Biot is actually the better scientist
Jed Buchwald (1:13:38.880)
in a lot of ways, but Arago is furious about this. So furious that he actually demands and
Jed Buchwald (1:13:46.800)
forces the leader of French science, Laplace, the Marquis de Laplace and cohorts to write a note in
Jed Buchwald (1:13:57.360)
the published journal saying, oh, excuse us, actually Arago, et cetera, et cetera, blah, blah.
Lex Fridman (1:14:05.760)
So Arago continues to just hold this antipathy and fear of Biot. So what happens? 1815,
Jed Buchwald (1:14:17.920)
Napoleon is finished at Waterloo. A young Frenchman by the name of Augustin Fresnel
Jed Buchwald (1:14:24.240)
who was in the army is going back to his home on the north coast of France in Normandy,
Jed Buchwald (1:14:31.040)
passes through Paris. Arago is friends with Fresnel's uncle who's the head of the École des
Jed Buchwald (1:14:39.360)
Beaux Arts at the time. Anyway, Fresnel is already interested in certain things in light
Lex Fridman (1:14:45.680)
and he talks to Arago. Arago tells him a few things. Fresnel goes home and Fresnel is a
Jed Buchwald (1:14:51.200)
brilliant experimenter. He observes things and he's a very good mathematician, calculates things,
Jed Buchwald (1:15:00.080)
he writes something up, he sends it to Arago. Arago looks at it and Arago says to himself,
Jed Buchwald (1:15:06.080)
I can use this to get back at Biot. He brings Fresnel to Paris, sets him up in
Jed Buchwald (1:15:13.200)
a room at the observatory where Arago is for Fresnel to continue his work. Paper after paper
Jed Buchwald (1:15:19.680)
comes out undercutting everything Biot had done. What is it about jealousy and just envy that
Lex Fridman (1:15:31.200)
could be an engine of creativity and productivity versus like an Einstein where it seems like not?
Jed Buchwald (1:15:40.960)
I don't know which one is better. I guess it depends on the personality. Both are useful
Jed Buchwald (1:15:44.480)
engines in science. Well, in this particular story, it's maybe even more interesting because
Jed Buchwald (1:15:51.280)
Fresnel himself, the young guy, he knew what Arago was doing with him and he didn't like it.
Jed Buchwald (1:15:58.080)
He didn't want to get with, he wrote his brother said, I don't want to get in an argument with Biot,
Jed Buchwald (1:16:03.120)
I just want to do my stuff. Arago is using him, but it's because Arago kept pushing him to go
Jed Buchwald (1:16:10.000)
into certain areas that stuff kept coming out. Yeah. Ego is beautiful. Okay. But back to Newton,
Jed Buchwald (1:16:21.040)
there's a bunch of things I want to ask, but sort of, let's say since we're on the Leibniz
Lex Fridman (1:16:26.160)
and the topic of drama, let me ask another drama question. Why was Newton a complicated man?
Jed Buchwald (1:16:31.760)
We're breaking news today. This is like. Right. Why was he complicated? His
Jed Buchwald (1:16:41.760)
brain structure was different. I don't know why. He had a complicated young life, as we've said.
Jed Buchwald (1:16:48.720)
He had always been very self contained and solitary. He had acquaintances and friends.
Lex Fridman (1:16:56.720)
And when he moved to London eventually, he had quite a career. A career, for instance, that led
Jed Buchwald (1:17:02.560)
him when he was famous by then, the 1690s, he moves to London. He becomes first warden of the
Jed Buchwald (1:17:10.560)
mint. The mint is what produces coins and coinage was a complicated thing because there was
Jed Buchwald (1:17:15.520)
counterfeiting going on. And he becomes master of the mint to the extent. And a guy at MIT wrote a
Jed Buchwald (1:17:23.360)
book about this a little bit. We wrote something on it too. I forget his name was Levin. That Newton
Jed Buchwald (1:17:30.480)
sent investigators out to catch these guys and sent at least one of them, a famous one named
Jed Buchwald (1:17:36.640)
Challener to the gallows. And one of the reasons he probably was so particularly angry at Challener
Jed Buchwald (1:17:47.280)
was Challener had apparently said some nasty things about Newton in front of parliament at
Jed Buchwald (1:17:52.800)
some point. Fair enough. That was apparently not a good idea. Well, he had a bit of a temper. So
Jed Buchwald (1:17:58.800)
you had a bit of a temper. Clearly. But he even as a young man at Cambridge, though he doesn't come
Jed Buchwald (1:18:08.560)
from wealth, he attracts people who recognize his smarts. There's a young fellow named Humphrey
Jed Buchwald (1:18:16.800)
Newton shared his rooms. These students always shared rooms with one another, became his kind
Jed Buchwald (1:18:23.680)
of amanuensis to write down what Newton was doing and so on. And there were others over time who he
Jed Buchwald (1:18:34.240)
befriended in various ways and so on. He was solitary. He had, as far as we know, no relationships
Lex Fridman (1:18:42.880)
with either women or men in anything other than a formal way. The only...
Jed Buchwald (1:18:49.360)
Those get in the way relationships.
Jed Buchwald (1:18:51.360)
Right. Well, I mean, I don't know if he was close to his mother. I mean, she passed away,
Jed Buchwald (1:18:58.320)
everything left him. He went to be with her after she died. He was close to his niece,
Jed Buchwald (1:19:04.160)
Catherine Barton, who basically came to run his household when he moved to London and so on. And
Jed Buchwald (1:19:13.200)
she married a man named Conduit, who became one of the people who controlled Newton's legacy
Jed Buchwald (1:19:21.920)
later on and so on. And you can even see the townhouse that Newton lived in, in those days,
Jed Buchwald (1:19:29.840)
still there.
Jed Buchwald (1:19:30.400)
All right. So there's the story of Newton coming up with quite a few ideas during a pandemic.
Jed Buchwald (1:19:38.720)
We're on the outskirts of a pandemic ourselves.
Lex Fridman (1:19:42.640)
Right.
Lex Fridman (1:19:43.040)
And a lot of people use that example as motivation for everybody while they're
Lex Fridman (1:19:47.360)
in lockdown to get stuff done. So what's that about? Can you tell the story of that?
Jed Buchwald (1:19:53.120)
Well, I can. Let me first say that, of course, we've been teaching over Zoom lately.
Lex Fridman (1:19:58.080)
There was no Zoom back then?
Jed Buchwald (1:20:00.080)
There was no Zoom back then. Although it wouldn't have made much difference because the story was
Jed Buchwald (1:20:04.480)
Newton was so complicated in his lectures that at one point, Humphrey Newton actually said that
Jed Buchwald (1:20:09.920)
he might as well have just been lecturing to the walls because nobody was there
Lex Fridman (1:20:13.600)
to listen to it. So what difference?
Lex Fridman (1:20:15.680)
Also not a great teacher, huh?
Lex Fridman (1:20:18.880)
If you look at his optical notes, if that's what he's reading from...
Jed Buchwald (1:20:22.960)
Oh, boy. Okay.
Lex Fridman (1:20:23.840)
No.
Lex Fridman (1:20:27.920)
So what can you say about that whole journey through the pandemic that resulted in so much
Lex Fridman (1:20:35.120)
innovation in such a short amount of time?
Jed Buchwald (1:20:37.440)
Well, I mean, there's two times that he goes home. Would he have been able to do it and do do it if
Jed Buchwald (1:20:45.280)
he'd stayed at Cambridge? I think he would have. I don't think it really... Although I do like to
Jed Buchwald (1:20:50.640)
tell my advanced students when I lecture on the history of physics to the physics and chemistry
Jed Buchwald (1:20:55.520)
students, especially we've been doing it over Zoom last year, when we get to Newton and so on,
Jed Buchwald (1:21:00.560)
because these kids are, you know, 21, 22, I like to say, well, you know, when Newton was your age
Lex Fridman (1:21:06.960)
and he had to go home during an epidemic, do you know what he produced?
Lex Fridman (1:21:12.320)
So can you actually summarize this for people who don't know how old was Newton and what did
Jed Buchwald (1:21:16.320)
he produce? Well, Newton goes up to Cambridge, as it said, when he's 18 years old in 1660.
Lex Fridman (1:21:24.640)
And the so called miraculous year, the annus mirabilis, where you get the development
Jed Buchwald (1:21:32.080)
in the calculus and in optical discoveries, especially, is 1666, right? So he's, what,
Jed Buchwald (1:21:40.000)
24 years old at the time. But judging from the notebooks that I mentioned, he's already,
Jed Buchwald (1:21:48.400)
before that, come to an awful lot of developments over the previous couple of years.
Jed Buchwald (1:21:56.720)
Does it have much to do with the fact that he twice went home? It is true that the optical
Jed Buchwald (1:22:03.280)
experiments that we talked of a while ago with the light on the wall moving up and down were done at
Jed Buchwald (1:22:08.400)
home. In fact, you can visit the very room he did it in to this day. Yeah, it's very cool.
Lex Fridman (1:22:15.120)
And if you look through the window in that room, there is an apple tree out there in the garden.
Lex Fridman (1:22:21.280)
So you might be wrong about this. You're lying to me. Maybe there's an apple
Lex Fridman (1:22:25.600)
involved after all. Well, it's not the same apple tree, but it's cuttings.
Lex Fridman (1:22:29.760)
How do you know?
Lex Fridman (1:22:31.440)
They don't last that long, but it's 400 years ago.
Jed Buchwald (1:22:34.560)
Oh, wow. I continue with the dumbest questions. Okay. So you're saying that perhaps going home
Jed Buchwald (1:22:43.040)
was not... It may have given him an opportunity to work things through. And after all, he did make
Jed Buchwald (1:22:50.160)
use of that room and he could do things like put a shade over the window, move things around,
Jed Buchwald (1:22:55.520)
cut holes in it and do stuff. Probably in his rooms at Cambridge, maybe not. Although when he
Jed Buchwald (1:23:03.120)
stayed at Cambridge subsequently and became a fellow, and then the second Lucasian professor
Jed Buchwald (1:23:10.960)
there, he was actually really the first one because Isaac Barrow, who was the mathematician,
Jed Buchwald (1:23:18.080)
professor of optics who recognized Newton's genius, gave up what would have been his position
Jed Buchwald (1:23:24.320)
because he recognized... Newton may not have learned too much from him, although they did
Jed Buchwald (1:23:30.000)
interact. And so Newton was the first Lucasian professor really, the one that Stephen Hawking
Jed Buchwald (1:23:35.920)
held till he died. And we know that the rooms that he had there at Cambridge subsequently,
Jed Buchwald (1:23:44.480)
those rooms are still there, he built an all chemical furnace outside, did all sorts of stuff
Jed Buchwald (1:23:49.360)
in those rooms. And don't forget, you didn't have to do too much as a Lucasian professor.
Jed Buchwald (1:23:57.280)
Every so often you had to go give these lectures, whether anybody was there or not,
Lex Fridman (1:24:01.840)
and deposit the notes for the future, which is how we have all those things.
Jed Buchwald (1:24:09.920)
Oh, they were stored and now we have them. And now we know just how terrible of a teacher Newton
Jed Buchwald (1:24:15.280)
was. Yeah, but we know how brilliant these notes are. In fact, the second volume of Newton's,
Jed Buchwald (1:24:20.560)
of the notes really on the great book that he published, The Optics, which he published in 1704,
Jed Buchwald (1:24:27.920)
that has just been finished with full annotations and analysis by the greatest analyst of Newton's
Jed Buchwald (1:24:35.920)
optics, Alan Shapiro, who retired a few years ago at the University of Minnesota and been working
Jed Buchwald (1:24:42.080)
on Newton's optics ever since I knew him and before, and I've known him since 1976.
Jed Buchwald (1:24:48.880)
Is there something you could say broadly about either that work on optics or Principia itself
Lex Fridman (1:24:57.760)
as something that I've never actually looked at as a piece of work?
Jed Buchwald (1:25:04.640)
Is it powerful in itself or is it just an important moment in history in terms of the
Jed Buchwald (1:25:12.400)
amount of inventions that are within, the amount of ideas that are within, or is it a really powerful
Jed Buchwald (1:25:19.280)
work in itself? Well, it is a powerful work in itself. You can see this guy coming to grips with
Lex Fridman (1:25:27.680)
and pushing through and working his way around complicated and difficult issues, melding
Jed Buchwald (1:25:34.880)
experimental situations which nobody had worked with before, even discovering new things,
Jed Buchwald (1:25:42.400)
trying to figure out ways of putting this together with mathematical structures,
Jed Buchwald (1:25:46.320)
succeeding and failing at the same time. And we can see him doing that.
Jed Buchwald (1:25:52.480)
I mean, what is, what is contained within Principia? I don't even know in terms of the
Lex Fridman (1:25:58.640)
scope of the work. Is it the entirety of the body of work of Newton?
Lex Fridman (1:26:04.240)
No, no, no, no. The Principia Mathematica...
Lex Fridman (1:26:06.720)
Is it calculus?
Lex Fridman (1:26:08.480)
Well, all right. So the Principia is divided into three books.
Jed Buchwald (1:26:14.800)
Excellent.
Jed Buchwald (1:26:16.640)
Book one contains his version of the laws of motion and the application of those laws
Jed Buchwald (1:26:23.440)
to figure out when a body moves in certain curves and is forced to move in those curves
Jed Buchwald (1:26:30.320)
by forces directed to certain fixed points, what is the nature of the mathematical formula
Jed Buchwald (1:26:37.680)
for those forces? That's all that book one is about. And it contains not the kind of version
Jed Buchwald (1:26:44.240)
of the calculus that uses algebra of the sort that I was trying to explain before,
Lex Fridman (1:26:50.080)
but is done in terms of ratios between geometric line segments when one of the line segments goes
Jed Buchwald (1:27:00.960)
very, very small. It's called the kind of limiting procedure, which is calculus, but it's a geometrically
Jed Buchwald (1:27:08.320)
structured, although it's clearly got algebraic elements in it as well. And that makes the
Jed Buchwald (1:27:14.960)
Principia's mathematical structure rather hard for people who aren't studying it today to
Jed Buchwald (1:27:22.880)
go back to. Book two contains his work on what we now call hydrostatics and a little bit about
Jed Buchwald (1:27:34.080)
hydrodynamics, a fuller development of the concept of pressure, which is a complicated concept.
Lex Fridman (1:27:42.880)
And book three applies what he did in book one to the solar system. And it is successful
Jed Buchwald (1:27:51.680)
partially because the only way that you can exactly solve, the only types of problems you
Jed Buchwald (1:27:59.920)
can exactly solve in terms of the interactions of two particles governed by gravitational force
Jed Buchwald (1:28:08.320)
between them is for only two bodies. If there's more than two, let's say it's A, B, and C,
Jed Buchwald (1:28:15.440)
A acts on B, B acts on C, C acts on A, you cannot solve it exactly. You have to develop techniques.
Jed Buchwald (1:28:24.160)
The fullest sets of techniques are really only developed about 30 or 40 years after Newton's
Jed Buchwald (1:28:29.840)
death by French mathematicians like Laplace. Newton tried to apply his structure to the
Jed Buchwald (1:28:40.080)
sun, earth, moon, because the moon's motion is very complicated. The moon, for instance,
Jed Buchwald (1:28:47.200)
exactly repeats its observable position among the stars only every 19 years.
Jed Buchwald (1:28:53.520)
That is, if you look up where the moon is among the stars at certain times and it changes,
Jed Buchwald (1:28:59.280)
it's complicated. That's, by the way, that was discovered by the Babylonians.
Lex Fridman (1:29:06.800)
That fact, the 19 years.
Jed Buchwald (1:29:08.320)
Thousands of years ago, yes.
Lex Fridman (1:29:09.840)
And then you have to load that little piece of data and how do you make sense of it? I mean,
Jed Buchwald (1:29:13.680)
that is data and you have to fit it.
Lex Fridman (1:29:15.280)
And it's complicated. So Newton actually kind of reverse engineered a technique that had been
Jed Buchwald (1:29:21.920)
developed by a man named Horrocks, using certain laws of Kepler's to try and get around this thing.
Lex Fridman (1:29:28.480)
And Newton then sort of, my understanding, I've never studied this, has reversed,
Jed Buchwald (1:29:33.600)
sort of reversed it and fit it together with his force calculations by way of an approximation.
Lex Fridman (1:29:40.480)
And was able to construct a model to make some predictions?
Jed Buchwald (1:29:46.080)
It fit things backwards pretty well.
Lex Fridman (1:29:49.680)
Okay. Where does data fit into this? We kind of earlier in the discussion
Lex Fridman (1:29:57.360)
mentioned data as part of the scientific method. How important was data to Newton?
Lex Fridman (1:30:04.560)
Okay.
Lex Fridman (1:30:05.440)
So like you mentioned Prism and playing with it and looking at stuff and then coming up with
Lex Fridman (1:30:11.120)
calculations and so on. Where does data fit into any of his ideas?
Jed Buchwald (1:30:14.720)
All right. Well, let me say two things first. One, we rarely use the phrase scientific method
Jed Buchwald (1:30:20.800)
anymore because there is no one easily describable such method. I mean, humans have been
Jed Buchwald (1:30:28.880)
playing around with the world and learning how to repetitively do things and make things happen
Lex Fridman (1:30:34.160)
ever since, you know, humans became humans.
Lex Fridman (1:30:37.200)
Do you have a preferred definition of the scientific method?
Lex Fridman (1:30:41.280)
Do you have a preferred definition of the scientific method? What are the various?
Jed Buchwald (1:30:46.480)
No, I don't. I prefer to talk about
Jed Buchwald (1:30:52.880)
the considered manipulation of artificial structures to produce results that can be
Jed Buchwald (1:31:02.160)
worked together with schemes to construct other devices and make
Lex Fridman (1:31:08.160)
predictions, if you will, about the way such things will work.
Lex Fridman (1:31:11.360)
So ultimately, it's about producing other devices. It's like leads you down a...
Jed Buchwald (1:31:16.080)
I think so, principally. I mean, you may have data, if you will, like astronomical data
Jed Buchwald (1:31:23.280)
obtained otherwise and so on, but yes. But number two here is this question of data. What is data
Jed Buchwald (1:31:30.640)
in that sense? See, when we talk about data today, we have a kind of complex notion, which
Jed Buchwald (1:31:38.800)
reverts to even issues of statistics and measurement procedures and so on. So let me put it to you this
Jed Buchwald (1:31:47.920)
way. So let's say I had a ruler in front of me and it's marked off in little black marks separated
Jed Buchwald (1:31:55.760)
by, let's say, distances called a millimeter. Okay. Now I make a mark on this piece of paper here.
Lex Fridman (1:32:03.280)
So I made a nice black mark, right? Nice black mark. And I ask you, I want you to measure that
Lex Fridman (1:32:09.920)
and tell me how long it is. You're going to take the ruler, you're going to put it next to it,
Lex Fridman (1:32:17.200)
and you're going to look, and it's not going to sit, even if you put one end in the middle,
Jed Buchwald (1:32:24.320)
even if you put one end as close as you can on one black mark, the other end probably isn't going to
Jed Buchwald (1:32:29.680)
be exactly on a black mark. Well, you'll say it's closer to this or that. You'll write down a number
Lex Fridman (1:32:35.440)
and I say, okay, take the ruler away a minute. I take this away, come back in five minutes,
Jed Buchwald (1:32:40.160)
put the piece of paper down, do it again. You're going to probably come up with a different number
Lex Fridman (1:32:45.520)
and you're going to do that a lot of times. And then if I tell you, I want you to give me your
Lex Fridman (1:32:50.000)
best estimate of what the actual length of that thing is, what are you going to do?
Lex Fridman (1:32:55.520)
You're going to average all of these numbers. Why?
Lex Fridman (1:33:04.480)
Statistics.
Jed Buchwald (1:33:06.000)
Well, yes, statistics. There's lots of ways of going around it,
Lex Fridman (1:33:10.800)
but the average is the best estimate on the basis of what's called the central limit theorem,
Jed Buchwald (1:33:16.720)
a statistical theorem. We're talking about things that were not really developed until the 1750s,
Lex Fridman (1:33:23.840)
60s and 70s. Newton died in 1727.
Jed Buchwald (1:33:26.880)
The intuition perhaps was there.
Lex Fridman (1:33:28.800)
Not really. I'll tell you what people did, including Newton, although Newton is
Jed Buchwald (1:33:33.440)
partially the one exception. We talked a while ago about this guy, Christian Huygens.
Jed Buchwald (1:33:39.040)
He measured lots of things and he was a good mechanic himself. He and his brother ground
Jed Buchwald (1:33:45.680)
lenses. Huygens, I told you, developed the first pendulum mechanism, pendulum driven clock with a
Jed Buchwald (1:33:51.680)
mechanism and so on. Also a spring watch where he got into a controversy with Hooke over that,
Jed Buchwald (1:33:58.080)
by the way.
Lex Fridman (1:34:00.240)
What's with these mechanics and the controversy?
Jed Buchwald (1:34:04.800)
Well, we also have Huygens's notes. They're preserved at Leiden University in Holland,
Jed Buchwald (1:34:12.960)
he's Dutch, for his work in optics, which was extensive. We don't have time to go into that,
Jed Buchwald (1:34:18.960)
except the following. A number of years ago, I went through those things because
Jed Buchwald (1:34:23.920)
in this optical theory that he had, there are four numbers that you've got to be able to get
Jed Buchwald (1:34:30.480)
good numbers on to be able to predict other things. What would we do today? What in fact
Jed Buchwald (1:34:37.360)
was done at the end of the 18th century when somebody went back to this? I told you to do
Jed Buchwald (1:34:42.480)
with the ruler. You make a lot of measurements and average results. We have Huygens's notes.
Jed Buchwald (1:34:48.240)
He did make a lot of measurements, one after the other, after the other. But when he came to use
Jed Buchwald (1:34:56.240)
the numbers for calculations, and indeed when he published things at the end of his life,
Jed Buchwald (1:35:03.120)
he gives you one number and it's not the average of any of them. It's just one of them. Which one
Jed Buchwald (1:35:09.360)
was it? The one that he thought he got so good at working by practice that he put down the one he
Jed Buchwald (1:35:20.080)
was most confident in. That was the general procedure at the time. You wouldn't publish
Jed Buchwald (1:35:26.880)
a paper in which you wrote down six numbers and said, well, I measured this six times.
Jed Buchwald (1:35:32.320)
Let me put them together. None of them is really, they would have said, the right number,
Lex Fridman (1:35:37.360)
but I'll put them together and give you a good number. No, you would have been thought of that,
Jed Buchwald (1:35:42.240)
you know, you don't know what you're doing. Yeah. By the way, there's just an inkling of value to
Jed Buchwald (1:35:49.440)
that approach. Just an inkling. We sometimes use statistics as like a thing that like, oh,
Jed Buchwald (1:35:56.800)
that solves all the problems. We'll just do a lot of it and we'll take the average or whatever it
Jed Buchwald (1:36:01.760)
is. As many excellent books on mathematics have highlighted the flaws in our approach to certain
Jed Buchwald (1:36:08.640)
sciences that rely heavily on statistics. Okay. Let me ask you again for a friend about this
Jed Buchwald (1:36:16.800)
alchemy thing. You know, it'd be nice to create gold, but it also seems to come into play quite
Jed Buchwald (1:36:24.160)
a bit throughout the history of science, perhaps in positive ways in terms of its impact. Can you
Jed Buchwald (1:36:30.320)
say something to the history of alchemy? A little bit. Sure. It used to be thought two things. One,
Jed Buchwald (1:36:40.480)
that alchemy, which dates certainly back to the Islamic period in Islam, you're talking, you know,
Jed Buchwald (1:36:49.040)
11th, 12th, 13th centuries among Islamic natural philosophers and experimenters.
Lex Fridman (1:36:54.720)
But it used to be thought that alchemy, which picked up strikingly in the 16th century, 1500s
Lex Fridman (1:37:03.360)
and thereabouts, was a sort of mystical procedure involving all sorts of strange notions and so on.
Lex Fridman (1:37:12.080)
And that's not entirely untrue, but it is substantially untrue in that alchemists were
Jed Buchwald (1:37:20.240)
engaged in what was known as chrysopoeia, that is looking for ways to transform invaluable materials
Jed Buchwald (1:37:32.480)
into valuable ones. But in the process of doing so or attempting to do so, they learned how to
Jed Buchwald (1:37:42.000)
create complex amalgams of various kinds. They used very elaborate apparatus, glass
Jed Buchwald (1:37:49.920)
alembics in which they would use heat to produce chemical decompositions. They would write down and
Jed Buchwald (1:37:57.360)
observe these compositions. And many of the so called really strange looking alchemical formulas
Lex Fridman (1:38:03.840)
and statements where they'll say something like, I can't produce it, but it'll be the soul of
Jed Buchwald (1:38:09.360)
Mars will combine with this, et cetera, et cetera. These, it has been shown, are almost all actual
Jed Buchwald (1:38:18.720)
formulas for how to engage in the production of complex amalgams and what to do. And by the time
Jed Buchwald (1:38:26.960)
of Newton, Newton was reading the works of a fellow by the name of Starkey, who actually came
Jed Buchwald (1:38:34.960)
from Harvard shortly before, in which things had progressed, if you will, to the point where
Jed Buchwald (1:38:45.360)
the procedure turns into what historians call chrysopoeia, which basically runs into the notion
Jed Buchwald (1:38:52.640)
of thinking that these things are made out of particles. This is the mechanical philosophy.
Jed Buchwald (1:39:00.000)
This is the mechanical philosophy. Can we engage in processes, chemical processes to rearrange these
Jed Buchwald (1:39:06.800)
things, which is not so stupid after all. I mean, we do it, except we happen to do it in reactors,
Jed Buchwald (1:39:12.800)
not in chemical processes, unless of course it had happened that cold fusion had worked,
Jed Buchwald (1:39:18.560)
which it didn't. Not yet. Well, right. So that's the way they're thinking about these things.
Jed Buchwald (1:39:26.240)
There's a kind of mix. And Newton engages extensively in those sorts of manipulations.
Jed Buchwald (1:39:32.320)
In fact, more in that than almost anything else, except for his optical investigations. If you look
Jed Buchwald (1:39:41.360)
through the latter parts of the 1670s, the last five, six, seven years or so of that,
Jed Buchwald (1:39:47.440)
there's more on that than there is on anything else. He's not working on mechanics. He's pretty
Jed Buchwald (1:39:53.280)
much gone pretty far in optics. He'll turn back to optics later on. So optics and alchemy.
Lex Fridman (1:40:00.400)
So what you're saying is Isaac Newton liked shiny things. Well, actually, if you go online and look
Jed Buchwald (1:40:07.360)
at what Bill Newman, the professor at Indiana, at Bloomington, Indiana has produced, you'll find
Jed Buchwald (1:40:13.680)
the very shiny thing called the star regulus, which Newton describes as having produced according to
Jed Buchwald (1:40:19.760)
a particular way, which Newman figured out and was able to do it. And it's very shiny.
Lex Fridman (1:40:25.920)
There you go. Proves the theorem. Can I ask you about God, religion and its role in Newton's life?
Lex Fridman (1:40:34.720)
Was there helpful, constructive or destructive influences of religion in his work and in his life?
Jed Buchwald (1:40:47.120)
Well, there you begin to touch on a complex question. The role that God played would be an
Jed Buchwald (1:40:55.520)
interesting question to answer should one go and be able to speak with this invisible character
Jed Buchwald (1:41:00.400)
who doesn't exist. But putting that aside for the moment. Yeah, we don't like to talk about others
Jed Buchwald (1:41:05.200)
while they're not here. So, right. Newton is a deeply religious man, not unusually so,
Jed Buchwald (1:41:12.560)
of course, for the time. And clearly, his upbringing and perhaps his early experiences
Jed Buchwald (1:41:24.960)
have exacerbated that in a number of ways that he takes a lot of things personally. And he finds
Jed Buchwald (1:41:32.080)
perhaps solace in thinking about a sort of governing, abstract, rulemaking, exacting deity.
Jed Buchwald (1:41:45.600)
I think there is little question that his conviction that you can figure things out has
Jed Buchwald (1:41:56.160)
a fair bit to do with his profound belief that this rulemaker doesn't do things arbitrarily.
Jed Buchwald (1:42:06.720)
Newton does not think that miracles have happened since maybe the time of Christ, if then,
Lex Fridman (1:42:14.080)
and not in the same way. He was, for instance, an anti Trinitarian. He did not hold that Christ
Jed Buchwald (1:42:20.000)
had a divine being, but was rather endowed with certain powers by the rulemaker and whatnot.
Lex Fridman (1:42:28.240)
And he did not think that some of the tales of the Old Testament with various miracles and so on
Jed Buchwald (1:42:38.720)
occurred in anything like that way. Some may have, some may not have. Like everybody else,
Jed Buchwald (1:42:44.720)
of course, he did think that creation had happened about 6,000 years ago. Wait, really? Oh, yeah,
Jed Buchwald (1:42:51.200)
sure. Well, biblical chronology can give you a little bit about that. It's a little controversial,
Lex Fridman (1:42:56.640)
but sure. Interesting. Wow. The deity created the universe 6,000 years ago. And that didn't
Jed Buchwald (1:43:06.320)
interfere with his playing around with the sun and the moon? No, because he's figuring out,
Jed Buchwald (1:43:12.480)
he's watching the brilliant construction that this perfect entity did 6,000 years ago.
Jed Buchwald (1:43:21.600)
Yeah, has produced. Plus or minus a few years. Well, if you go with Bishop Boster, it's 4004 BCE.
Jed Buchwald (1:43:30.080)
Want to be precise about it. We always, and this is a serious program, we always want to be precise.
Jed Buchwald (1:43:36.080)
Okay. Let me ask another ridiculous question. If Newton were to travel forward in time
Lex Fridman (1:43:45.440)
and visit with Einstein and have a discussion about space time and general relativity,
Jed Buchwald (1:43:54.880)
that conception of time and that conception of gravity, what do you think that discussion will go
Jed Buchwald (1:43:59.600)
like? Put that way, I think Newton would sit there in shock and say, I have no idea what you're
Jed Buchwald (1:44:07.120)
talking about. If on the other hand, there's a time machine, you go back and bring a somewhat
Jed Buchwald (1:44:13.440)
younger Newton, not a man my age, say. I mean, he lived a long time into his mid eighties,
Lex Fridman (1:44:22.320)
but take him when he's in his forties, let's say, bring him forward and don't immediately
Jed Buchwald (1:44:27.280)
introduce him to Einstein. Let's take him for a ride on a railroad. Let him experience the
Jed Buchwald (1:44:33.760)
railroad. Oh, that's right. Take him around and show him a sparking machine. He knows about sparks,
Jed Buchwald (1:44:45.920)
sending off sparks. Show him wires, have him touch the wires and get a little shock.
Jed Buchwald (1:44:52.320)
Show him a clicking telegraph machine of the kind. Then let him hear the clicks in a telephone
Jed Buchwald (1:45:01.600)
receiver and so on. Do that for a couple of months. Let him get accustomed to things.
Jed Buchwald (1:45:08.480)
Then take him into, not Einstein yet, let's say we're taking him into the 1890s. Einstein is
Jed Buchwald (1:45:14.880)
young man then. We take him into some of the laboratories. We show him some of the equipment,
Jed Buchwald (1:45:21.040)
the devices, not the most elaborate ones. We show him certain things. We educate him
Jed Buchwald (1:45:26.880)
bit by bit. On optics, maybe focus on that. Certainly on optics. You begin to show him
Jed Buchwald (1:45:32.960)
things. He's a brilliant human being. I think bit by bit, he would begin to see what's going on.
Lex Fridman (1:45:42.480)
But if you just dumped him in front of Einstein, he'd sit there, his eyes would glaze over.
Jed Buchwald (1:45:46.640)
I mean, I guess it's almost a question of how big of a leap, how many leaps have been taken
Jed Buchwald (1:45:57.760)
in science that go from Newton to Einstein. We sometimes in a compressed version of history
Jed Buchwald (1:46:02.960)
think that not much. Oh, that's totally wrong. A lot. Huge amounts in multifarious ways
Jed Buchwald (1:46:13.200)
involving fundamental conceptions, mathematical structures, the evolution of novel experimentation
Lex Fridman (1:46:19.360)
and devices, the organization. It's not everything. Everything. I mean, to a point where I wonder
Jed Buchwald (1:46:25.600)
even if Newton was like, you said 40, but even like 30. So he's very, like if you would be able
Jed Buchwald (1:46:35.120)
to catch up with the conception of everything. I wonder as a scientist, how much you load in from
Jed Buchwald (1:46:42.080)
age five about this world in order to be able to conceive of the world of ideas that push that
Jed Buchwald (1:46:50.400)
science forward. I mean, you mentioned the railroad and all those kinds of things. That might be
Jed Buchwald (1:46:56.480)
fundamental to our ability to invent even when it doesn't directly obviously seem relevant.
Jed Buchwald (1:47:02.000)
Well, yes. I mean, the railroad, the steam engine, the Watt engine, et cetera. I mean,
Jed Buchwald (1:47:13.840)
that was really the Watt engine was developed pretty... Although Watt knew Joseph Black,
Jed Buchwald (1:47:19.440)
a chemist scientist and so on, did stuff on heat, was developed pretty much independently of
Jed Buchwald (1:47:25.200)
the developing thoughts about heat at the time. But what it's not independent of is the evolution
Jed Buchwald (1:47:36.560)
of practice in the manufacture and construction of devices which can do things in extraordinarily
Jed Buchwald (1:47:45.200)
novel ways and the premium being gradually placed on calculating how you can make them more
Jed Buchwald (1:47:51.600)
efficient. That is of a piece with a way of thinking about the world in which you're controlling
Jed Buchwald (1:48:00.320)
things and working it. It's something that humans have been doing for a long time, but in this more
Jed Buchwald (1:48:07.040)
concerted and structured way, I think you really don't find it in the fullest sense until well into
Jed Buchwald (1:48:18.160)
the 1500s and really not fully until the 17th century later on. So Newton had this year of
Jed Buchwald (1:48:28.320)
miracles. I wonder if I could ask you briefly about Einstein and his year of miracles. I've
Jed Buchwald (1:48:34.560)
been reading, re reading, revisiting the brilliance of the papers that Einstein published in the year
Jed Buchwald (1:48:42.800)
1905, one of which won him the Nobel prize, the photoelectric effect, but also Brownian motion,
Lex Fridman (1:48:49.280)
special theory of relativity, and of course the old E equals MC squared.
Jed Buchwald (1:49:00.480)
Does that make sense to you that these two figures had such productive years
Jed Buchwald (1:49:05.520)
that there's this moment of genius? Maybe, maybe if we zoom out, I mean, I, my work is very much
Jed Buchwald (1:49:12.960)
in artificial intelligence, sort of wondering about the nature of intelligence. Like how did we,
Lex Fridman (1:49:20.000)
how did evolution on earth produce genius that could come up with so much in so little time?
Jed Buchwald (1:49:28.400)
To me, that gives me hope that one person can change the world in such a small amount of time.
Jed Buchwald (1:49:35.040)
Well, of course there are precedents for, in both Newton's and Einstein's cases for elements of
Lex Fridman (1:49:44.720)
what we're finding there. It's, you know, and so on. Well, I have no idea. You know,
Jed Buchwald (1:49:50.000)
I'm sure you must've read, it was a kind of a famous story that after Einstein died,
Jed Buchwald (1:49:54.880)
he donated his brain and they sliced it up to see if they could find something unusual there,
Jed Buchwald (1:50:00.240)
nothing unusual visibly in there. So I have, clearly there are people who for various reasons,
Jed Buchwald (1:50:11.520)
maybe both intrinsic and extrinsic in the sense of experience and so on, are capable of coming
Jed Buchwald (1:50:19.280)
up with these extraordinary results. Many years ago, when I was a student, a friend of mine came
Jed Buchwald (1:50:27.280)
in and said, did you read about, did you read this? I forget what, anyway, there was a story
Jed Buchwald (1:50:31.440)
in the paper. It was about, I think it was a young woman who was, she couldn't speak and she was
Jed Buchwald (1:50:43.040)
somewhere on the autism spectrum. She could not read other people's affect in any ways, but she
Jed Buchwald (1:50:53.520)
could sit down at a piano and having heard it once and then run variations on the most complex
Lex Fridman (1:51:05.120)
pianistic works of Chopin and others, right? Now how?
Jed Buchwald (1:51:14.480)
Some aspect of our mind is able to tune in in some aspect of reality and become a master of it.
Lex Fridman (1:51:21.360)
And every once in a while, that means coming up with breakthrough ideas in physics.
Jed Buchwald (1:51:26.960)
Yep. How the heck does that happen? Who knows? Jed, I'd like to say thank you so much for spending
Jed Buchwald (1:51:33.520)
your valuable time with me today. It was a really fascinating conversation. I've learned so much
Jed Buchwald (1:51:37.680)
about Isaac Newton, who's one of the most fascinating figures in human history. So
Jed Buchwald (1:51:41.760)
thank you so much for talking to me. My pleasure. I enjoyed it very much.
Jed Buchwald (1:51:44.320)
Thanks for listening to this conversation with Jed Buchwald. To support this podcast,
Jed Buchwald (1:51:51.360)
please check out our sponsors in the description. And now let me leave you with some words from
Jed Buchwald (1:51:56.960)
Thomas Kuhn, a philosopher of science. The answers you get depend on the questions you ask.
Jed Buchwald (1:52:03.680)
Thank you for listening, and hope to see you next time.
Lex Fridman (20:03.120)
so manipulated it that what you've done is to produce what amounts to fake artifactual behavior
Jed Buchwald (20:10.880)
that doesn't really hold purely naturally. So where are we today in your sense to jump
Jed Buchwald (20:18.160)
around a little bit with the theory of everything? Maybe a quick kind of sense you have about the
Jed Buchwald (20:26.160)
journey in the world of physics that we're taking towards the theory of everything.
Jed Buchwald (20:30.320)
Well, I'm, of course, not a practicing physicist. I mean, I was trained in physics at Princeton
Jed Buchwald (20:36.560)
a long time ago. Until Thomas Kuhn stole you away.
Jed Buchwald (20:40.400)
More or less. I was taking graduate courses in those days in general relativity. I was an
Jed Buchwald (20:45.200)
undergraduate, but I moved up and then I took a course with him and...
Jed Buchwald (20:49.840)
Well, you made the mistake of being compelled by charismatic philosophers and never looked back.
Jed Buchwald (20:56.240)
I suppose so in a way. From what I understand, talking especially to my friends at Caltech,
Jed Buchwald (21:08.080)
like Kip Thorne and others, the fundamental notion is that actually the laws that even
Jed Buchwald (21:17.040)
at the deepest level we can sort of divine and work with in the universe that we inhabit are
Lex Fridman (21:26.560)
perhaps quite unique to this particular universe as it formed at the Big Bang.
Jed Buchwald (21:34.560)
The question is, how deep does it go? If you are very mathematically inclined, the prevailing notion
Jed Buchwald (21:43.200)
for several decades now has been what's called string theory, but that has not been able to
Jed Buchwald (21:53.360)
figure a way to generate probative experimental evidence, although it's pretty good apparently
Jed Buchwald (22:00.400)
at accommodating things. Then the question is, what's before the Big Bang? Actually,
Jed Buchwald (22:08.400)
the word before doesn't mean anything given the nature of time, but why do we have the
Jed Buchwald (22:17.280)
laws that prevail in our universe? Well, there is a notion that those laws prevail in our universe
Jed Buchwald (22:26.240)
because if they didn't, we wouldn't be here.
Jed Buchwald (22:30.560)
That's a bit of a cyclical, but nevertheless, a compelling definition. And there's all kinds
Jed Buchwald (22:35.600)
of things like it seems like the unification of those laws could be discovered by looking
Jed Buchwald (22:42.000)
inside of a black hole because you get both the general relativity and the quantum mechanics,
Jed Buchwald (22:45.920)
quantum field theory in there. Experimentally, of course, there's a lot of interesting ideas.
Jed Buchwald (22:51.920)
We can't really look close to the Big Bang. We can't look that far back. Caltech and MIT will
Jed Buchwald (22:57.920)
LIGO looking at gravitational waves, perhaps allows us to march backwards and so on. Yeah,
Lex Fridman (23:03.120)
it's really exciting space. And there's, of course, the theory of everything,
Jed Buchwald (23:07.920)
like with a lot of things in science, captivates the dreams of those who are perhaps completely
Jed Buchwald (23:13.200)
outside of science. It's the dream of discovering the key to the nature of how everything works.
Lex Fridman (23:21.360)
And that feels deeply human. That's perhaps the basic elements of what makes up a scientist in
Jed Buchwald (23:31.120)
the end is that curiosity, that longing to understand. Let me ask, you mentioned a disagreement
Jed Buchwald (23:39.600)
with Weinberg on reality. Could you elaborate a little bit? Well, obviously, I don't disagree
Jed Buchwald (23:48.320)
with Steve Weinberg on physics itself. I wouldn't know enough to even begin to do that. And clearly,
Jed Buchwald (23:55.280)
you know, he's one of the founders of the standard model and so on. And it works to a level of
Jed Buchwald (24:02.000)
accuracy that no physical theory has ever worked at before. I suppose the question in my mind is
Jed Buchwald (24:10.720)
something that in one way could go back to the philosopher Immanuel Kant in the 18th century,
Jed Buchwald (24:18.000)
namely, can we really ever convince ourselves that we have come to grips with something that is
Jed Buchwald (24:30.320)
not in itself knowable to us by our senses, or even except in the most remote way through the
Jed Buchwald (24:41.680)
complex instruments that we make as to what it is that underlies everything? Can we corral it
Jed Buchwald (24:48.960)
with mathematics and experimental structures? Yes. Do I think that a particular way of corraling
Jed Buchwald (24:57.760)
nature will inevitably play itself out? I don't know. It always has. I'll put it to you that way.
Lex Fridman (25:06.240)
So the basic question is, can we know reality? Is that the Kant question? Is that the Weinberg
Jed Buchwald (25:18.320)
question? We humans, with our brains, can we comprehend reality? Sounds like a very trippy
Jed Buchwald (25:28.960)
question because a lot of it rests on definitions of know and comprehend and reality. But
Jed Buchwald (25:34.480)
get to the bottom of it. It's turtles on top of turtles. Can we get to the bottom turtle and say
Jed Buchwald (25:44.080)
hello? Well, maybe I can put it to you this way in a way that I often begin discussions in a class
Jed Buchwald (25:56.240)
on the history of science and so on, and say, I'm looking at you. Yes. You are in fact a figment of
Jed Buchwald (26:07.120)
my imagination. You have a messed up imagination, yes. Well, what do I mean by that? If I were a
Jed Buchwald (26:15.040)
dragonfly looking at you, whatever my nervous system would form by way of a perceptual structure
Jed Buchwald (26:29.120)
would clearly be utterly different from what my brain and perceptual system altogether is forming
Lex Fridman (26:39.040)
when I look at you. Who's right? Is it me or the dragonfly?
Jed Buchwald (26:51.680)
Well, the dragonfly is certainly very impressive, so I don't know. But yes, the observer matters.
Lex Fridman (27:02.400)
What is that supposed to tell us about objective reality?
Jed Buchwald (27:06.240)
Well, I think it means that it's very difficult to get beyond the constructs that our perceptual
Jed Buchwald (27:16.080)
system is leading us to. When we make apparatus and devices and so on, we're still making things,
Jed Buchwald (27:25.120)
the results of which or the outputs of which we process perceptually in various ways.
Jed Buchwald (27:30.640)
An analogy I like to use with students sometimes is this. All right, they all have their laptops
Jed Buchwald (27:36.560)
open in front of them, of course. I've sent them something to read, and I say, okay, click on it
Lex Fridman (27:45.760)
and open it up. PDF opens up. I said, what are you looking at? They said, well, I'm looking at the
Jed Buchwald (27:51.920)
paper that you sent me. I said, no, you're not. What you're looking at is what you're looking at
Jed Buchwald (27:57.520)
is a stream of light coming off LEDs or LCDs coming off a screen. And I said, what happens when you
Jed Buchwald (28:06.000)
use your mouse and move that fake piece of paper on the screen around? What are you doing? You're
Jed Buchwald (28:12.320)
not moving a piece of paper around, are you? You're moving a construct around, a construct
Jed Buchwald (28:18.080)
that's being processed so that our perceptual system can interact with it in the way we
Jed Buchwald (28:24.080)
interact with pieces of paper. Yes. But it's not real. So, are there things outside of the reach
Jed Buchwald (28:34.800)
of science? Can you maybe, as an example, talk about consciousness? I'm asking for a friend
Jed Buchwald (28:43.120)
trying to figure this thing out. Well, boy, I mean, I read a fair bit of science, but I don't
Jed Buchwald (28:52.640)
know. I read a fair bit about that, but I certainly can't really say much about it.
Jed Buchwald (29:02.880)
I'm a materialist in the deepest sense of the term. I don't think there is anything out there
Jed Buchwald (29:09.280)
except material structures which interact in various ways. Do I think, for example,
Jed Buchwald (29:16.480)
that this bottle of water is conscious? No, I do not. Although, how would I know? I can't talk to
Jed Buchwald (29:23.920)
it. Yeah. But, so what do... It's a hypothesis you have. It's an opinion, an educated opinion
Jed Buchwald (29:29.760)
that may be very wrong. Well, I know that you're conscious because I can interact directly with you.
Lex Fridman (29:35.200)
But am I? Well, unless you're a figment of my imagination, of course. Or I'm a robot that's
Jed Buchwald (29:41.040)
able to generate the illusion of consciousness effectively enough to facilitate a good
Jed Buchwald (29:48.640)
conversation. Because we humans do want to pretend that we're talking to other conscious beings.
Jed Buchwald (29:52.560)
That's how we respect them. If it's not conscious, we don't respect them. We're not good at talking
Jed Buchwald (29:56.880)
to robots. That's true. Of course, we generalize from our own inner sense, which is the kind of
Jed Buchwald (30:01.280)
thing Descartes said from the beginning. We generalize from that. But I do think that
Jed Buchwald (30:07.120)
consciousness must be something, whatever it is, that occurs as a result of some particular
Jed Buchwald (30:14.240)
organizational structure of material elements. Does materialism mean that it's all within the
Jed Buchwald (30:24.400)
reach of science? My sense would be that, especially as neuroscience progresses more and more and
Jed Buchwald (30:35.680)
at Caltech, we just built a whole neuroscience arena and so on. And as more knowledge is gained
Jed Buchwald (30:44.320)
about the ways in which animals, when they behave, what patterns show up at various parts of the
Jed Buchwald (30:52.800)
brain and nervous system, and perhaps extending it to humans eventually as well, we'll get more of a
Jed Buchwald (31:00.480)
we'll get more of a handle on what brain activity is associated with experiences that we have as
Jed Buchwald (31:12.880)
humans. Can we move from the brain activity to the experiences in terms of our perception? No,
Jed Buchwald (31:20.560)
you can't. Perception is perception. That's the hypothesis, once again.
Jed Buchwald (31:26.560)
Maybe consciousness is just one of the laws of physics that's yet to be discovered. Maybe it
Jed Buchwald (31:35.760)
permeates all matter. Maybe it's as simple as trying to plug it in and plug into the ability
Jed Buchwald (31:44.800)
to generate and control that kind of law of physics that would crack open. Or we would understand
Jed Buchwald (31:52.000)
that the bottle of water is in fact conscious, just much less conscious than us humans,
Lex Fridman (31:56.880)
and then we would be able to generate beings that are more conscious.
Jed Buchwald (32:02.080)
Well, that'll be unfortunate. I'd have to stop drinking the water after that.
Lex Fridman (32:06.400)
Every time you take a sip, there's a little bit of suffering going on.
Jed Buchwald (32:11.360)
Right.
Lex Fridman (32:12.320)
What do you use the most interesting, beautiful moments in the history of science? What stands
Jed Buchwald (32:18.080)
out? And then we can pull at that thread.
Jed Buchwald (32:22.160)
Right. Well, I like to think of events that have a major impact and involve both beautiful,
Jed Buchwald (32:34.560)
conceptual, mathematical, if we're talking physical structures work, and are associated as
Jed Buchwald (32:41.440)
well with probing experimental situations. So among my favorites is one of the most famous,
Jed Buchwald (32:51.520)
which was the young Isaac Newton's work with the colors produced when you pass sunlight through a
Jed Buchwald (32:59.040)
prism. And why do I like that? It's not profoundly mathematical in one sense. It doesn't need it
Jed Buchwald (33:08.720)
initially. It needs the following though, which begins to show you I think a little bit about what
Jed Buchwald (33:14.320)
gets involved when you've got a smart individual who's trying to monkey around with stuff and
Jed Buchwald (33:19.440)
finds new things about it. First, let me say that the prevailing notion going back to antiquity
Jed Buchwald (33:26.560)
was that colors are produced in a sense by modifying or tinting white light, that they're
Jed Buchwald (33:34.720)
modifications of white light. In other words, the colors are not in the sunlight in any way.
Jed Buchwald (33:43.520)
Now, what Newton did following experiments done by Descartes before him who came to very different
Jed Buchwald (33:49.680)
conclusions, he took a prism. You might ask, where do you get prisms in the 1660s? County fairs,
Jed Buchwald (33:59.680)
they were very popular. They were pretty crude with bubbles in them and everything,
Lex Fridman (34:03.840)
but they produced colors. So you could buy them at county fairs and things very popular.
Lex Fridman (34:08.000)
Oh, so they were modifying the white light to create colors.
Jed Buchwald (34:11.360)
Well, they were creating colors from it, well known. And what he did was the following. He
Jed Buchwald (34:18.400)
was by this time, even though he's very young, a very good mathematician. And he could use the
Jed Buchwald (34:26.320)
then known laws for how light behaves when it goes through glass to calculate what should happen
Jed Buchwald (34:32.320)
if you took light from the sun, passed it from a hole, through a little hole, then hit the prism,
Jed Buchwald (34:39.600)
goes out of the prism, strikes a wall a long distance away and makes a splash of light,
Jed Buchwald (34:45.040)
never mind the colors for a moment, makes a splash of light there. He was very smart.
Jed Buchwald (34:50.400)
First of all, he abstracts from the colors themselves, even though that's what everybody's
Jed Buchwald (34:56.080)
paying attention to initially. Because what he knows is this, he knows that if you take
Jed Buchwald (35:01.760)
this prism and you turn it to a certain particular angle, that he knew what it should be because he
Jed Buchwald (35:09.760)
could calculate things. Very few other people in Europe at the time could calculate things like he
Jed Buchwald (35:16.320)
could. That if you turn the prism to that particular angle, then the sun, which is, of course, a
Jed Buchwald (35:23.280)
circle, when its light passes through this little hole and then into the prism on the far distant
Jed Buchwald (35:30.160)
wall, should still make a circle. But it doesn't. It makes a very long image. And this led him to a
Jed Buchwald (35:43.520)
very different conception of light, indicating that there are different types of light in the
Jed Buchwald (35:48.800)
sunlight. Now, to go beyond that, what's particularly interesting, I think, is the following.
Jed Buchwald (35:54.640)
When he published this paper, which got him into a controversy, he really didn't describe
Jed Buchwald (36:02.320)
at all what he did. He just gave you some numbers. Now, I just told you that you had to set this
Jed Buchwald (36:08.000)
prism at a certain angle, right? You would think, because we do have his notes and so on,
Jed Buchwald (36:16.320)
you would think that he took some kind of complicated measuring device to set the prism.
Lex Fridman (36:22.080)
He didn't. He held it in his hand. That's all. And he twiddled it around. And what was he doing?
Jed Buchwald (36:30.320)
It turns out that when you twiddle the prism around at the point where you should get a circle
Jed Buchwald (36:36.960)
from a circle, it also is the place where the image does not move very fast. So if you want
Jed Buchwald (36:43.840)
to get close to there, you just twiddle it. This is manipulative experimentation taking advantage
Jed Buchwald (36:52.880)
through his mathematical knowledge of the inherent inaccuracies that let you come to
Jed Buchwald (37:00.800)
exact conclusions, regardless of the built in problematics of measurement. He's the only one
Jed Buchwald (37:09.040)
I know of doing anything like that at the time. Yeah. Well, even still, there's very few people
Jed Buchwald (37:15.840)
that are able to have to calculate as well as he did to be a theoretician and an experimentalist,
Jed Buchwald (37:23.600)
like in the same moment. It's true, although until really well into the 20th century,
Jed Buchwald (37:35.360)
maybe the beginning of the 20th century, really, most of the most significant experimental results
Jed Buchwald (37:45.040)
produced in the 1800s, which laid the foundations for light, electricity, electrodynamics, and so on,
Jed Buchwald (37:53.520)
even hydrodynamics and whatnot, were also produced by people who are both excellent calculators,
Lex Fridman (38:02.960)
very talented mathematicians, and good with their hands experimentally.
Lex Fridman (38:11.360)
And then that led to the 21st century with Enrico Fermi that one of the last people that
Jed Buchwald (38:18.640)
was able to do that, both of those things very well, and that he built a little device
Jed Buchwald (38:25.200)
called an atomic bomb that has some positives and negatives.
Jed Buchwald (38:28.960)
Well, right. Of course, that actually did involve some pretty large scale elaborate
Jed Buchwald (38:34.640)
equipment too. Well, holding a prism in your hands.
Lex Fridman (38:38.800)
Right. No. What's the controversy that Newton got into with that paper when he published it?
Jed Buchwald (38:45.840)
Well, in a number of ways, it's a complicated story. There was a very talented character
Jed Buchwald (38:54.560)
known as a mechanic. Mechanic means somebody who was a craftsman who could build and make
Jed Buchwald (39:00.240)
really good stuff. And he was very talented. His name was Robert Hooke. And he was the guy who
Jed Buchwald (39:06.480)
at the weekly meetings of the Royal Society in London, and Newton's not in London, he's at
Jed Buchwald (39:11.280)
Cambridge, he's a young guy, he would demonstrate new things. And he was very clever. And he had
Jed Buchwald (39:18.160)
written a book, in fact, called the Micrographia, which by the way, he used a microscope to make
Jed Buchwald (39:26.480)
the first depictions of things like a fly's eye, the structure of, you know, it had a big influence.
Lex Fridman (39:31.920)
And in there, he also talked about light. And so he had a different view of light. And when he read
Lex Fridman (39:36.880)
what Newton wrote, he had a double reaction. On the one hand, he said, anything in there that is
Jed Buchwald (39:44.480)
correct, I already knew. And anything that I didn't already know, is probably not right anyway.
Jed Buchwald (39:51.680)
Trey Lockerbie I gotta love egos. Okay. Can we just step
Jed Buchwald (39:58.320)
back? Can you say who was Isaac Newton? What are the things he contributed to this world
Jed Buchwald (40:05.200)
in the space of ideas? Wow. Who was he? He was born in 1642,
Lex Fridman (40:20.000)
and near the small town of Grantham in England. In fact, the house he was born in,
Lex Fridman (40:26.080)
and that his mother died in is still there and can be visited.
Jed Buchwald (40:29.280)
His father died before he was born. And his mother eventually remarried a man named
Jed Buchwald (40:41.760)
Reverend Smith, whom Newton did not like at all. Because Reverend Smith took his mother away to
Jed Buchwald (40:52.160)
live with him a few miles away, leaving Newton to be brought up more or less by his grandmother
Jed Buchwald (40:57.200)
over there. And he had huge resentment about that his whole life.
Jed Buchwald (41:02.880)
I think that gives you a little inkling that a little bit of trauma in childhood,
Jed Buchwald (41:08.320)
maybe a complicated father son relationship can be useful to create a good scientist.
Jed Buchwald (41:13.920)
Could be, although this case, it would be right, the absent father, non father relationship,
Lex Fridman (41:19.120)
so to speak. He was known as a kid, little that we do know for being very clever about
Jed Buchwald (41:26.240)
flying kites. And there are stories about him putting candles and putting flying kites and
Jed Buchwald (41:34.640)
scaring the living devil out of people at night by doing that and things like that,
Jed Buchwald (41:39.120)
making things. Most of the physicists and natural philosophers I've dealt with actually,
Jed Buchwald (41:48.080)
as children, were very fond of making and playing with things. I can't think of one I know of who
Jed Buchwald (41:54.400)
wasn't actually, very good with their hands and whatnot. His mother wanted him to take over the
Jed Buchwald (42:06.640)
manor. It was a kind of farming manor. They were the class of what are known as yeomans.
Jed Buchwald (42:12.160)
There are stories that he wasn't very good at that. One day, one of the stories is he's sitting
Jed Buchwald (42:17.600)
out in the field and the cows come home without him and he doesn't know what's going on. Anyway,
Jed Buchwald (42:24.480)
had relatives and he manages to get to Cambridge, sent to Cambridge because he's known to be smart.
Jed Buchwald (42:30.960)
He's read books that he got from local dignitaries and some relatives. And he goes there as what's
Jed Buchwald (42:37.600)
known as a sub sizer. What does that mean? Well, it's not too pleasant. Basically, a sub sizer
Jed Buchwald (42:43.200)
was a student who had to clean the bed pans of the richer kids. That didn't last too long.
Jed Buchwald (42:50.960)
He makes his way and he becomes absorbed in some of the new ways of thinking that are being talked
Jed Buchwald (43:00.240)
about on the parts of Descartes and others as well. There's also the traditional curriculum,
Jed Buchwald (43:06.560)
which he follows. And we have his notes. We have his student notebooks and so on. We can see
Jed Buchwald (43:12.400)
gradually this young man's mind focusing and coming to grips with deeper questions of the
Jed Buchwald (43:20.240)
nature of the world and perception even, and how we know things and also probing and learning
Jed Buchwald (43:28.640)
mathematical structures to such an extent that he builds on some of the investigations that had been
Jed Buchwald (43:35.760)
done in the period before him to create the foundations of a way of investigating processes
Jed Buchwald (43:43.200)
that happen and change continuously instead of by leaps and bounds and so on, forming the
Jed Buchwald (43:50.000)
foundation of what we now call the calculus. Yeah. So can you maybe just paint a little bit
Jed Buchwald (43:56.160)
of a picture you've already started of what were the things that bothered him the most
Jed Buchwald (44:04.000)
that stood out to him the most about the traditional curriculum, about the way people
Jed Buchwald (44:11.280)
saw the world? You mentioned discrete versus continuous. Is there something where he began
Jed Buchwald (44:16.080)
thinking in a revolutionary way? Because it's fascinating. Most of us go to college,
Jed Buchwald (44:22.560)
Cambridge or otherwise, and we just kind of take what we hear as gospel, right? Like not gospel,
Lex Fridman (44:30.560)
but as like facts. You don't begin to sort of see how can I expand on this aggressively or how can
Jed Buchwald (44:39.440)
I challenge everything that I hear rigorously, mathematically through the... I mean, I don't even
Jed Buchwald (44:46.960)
know how rigorous the mathematics was at that point. I'm sure it was geometry and so on,
Jed Buchwald (44:52.480)
no calculus, huh? There are elements of what turned into the calculus that predate Newton,
Jed Buchwald (45:00.160)
but... How much rigor was there? How much... Well, rigor, no. And then, of course, no scientific
Jed Buchwald (45:06.560)
method. Not really. I mean, somewhat. I mean, appreciation of data. That is a separate question
Jed Buchwald (45:15.120)
from a question of method. Appreciation of data is a significant question as to what you do with
Jed Buchwald (45:20.960)
data. There's lots of things you're asking. I apologize. So maybe let's backtrack in the first
Jed Buchwald (45:26.320)
question. Was there something that was bothering him that he especially thought he could contribute
Jed Buchwald (45:32.640)
or work on? Well, of course, we can't go back and talk to him, but we do have these student
Jed Buchwald (45:38.480)
notebooks. There's two of them. One's called The Philosophical Questions and the other is called
Jed Buchwald (45:43.920)
The Waste Book. The Philosophical Questions has discussions of the nature of reality and
Jed Buchwald (45:49.840)
various issues concerning it. And The Waste Book has things that have to do with motion in various
Jed Buchwald (45:55.760)
ways, what happens in collisions and things of that sort. And it's a complicated story,
Lex Fridman (46:01.760)
but what's among the things that I think are interesting is he took notes in The Philosophical
Jed Buchwald (46:07.760)
Questions on stuff that was traditionally given to you in the curriculums going back several hundred
Jed Buchwald (46:17.120)
years, namely on what scholars refer to as scholastic or neo scholastic ways of thinking
Jed Buchwald (46:25.840)
about the world dating back to the reformulation of Aristotle in the Middle Ages by Thomas Aquinas
Jed Buchwald (46:32.800)
in the church. This is a totally different way of thinking about things, which actually connects to
Jed Buchwald (46:37.840)
something we were saying a moment ago. For instance, so I'm wearing a blue shirt and I will
Jed Buchwald (46:45.760)
sometimes ask students, where is the blue? And they'll usually say, well, it's in your shirt.
Lex Fridman (46:52.080)
And then some of them get clear and they say, well, no, you know, light is striking it,
Jed Buchwald (46:56.240)
photons are reemitted, they strike the back of your retina and et cetera, et cetera. And I said,
Jed Buchwald (47:01.360)
yes. What that means is that the blue is actually an artifact of our perceptual system considered as
Jed Buchwald (47:10.880)
the percept of blue. It's not out there, it's in here. That's not how things were thought about
Jed Buchwald (47:21.040)
well into the 16th century. The general notion dating back even to Aristotelian antiquity
Lex Fridman (47:28.800)
and formalized by the 12th century at Paris, Oxford and elsewhere is that qualities are there
Jed Buchwald (47:39.120)
in the world. They're not in us. We have senses and our senses can be wrong. You could go blind,
Jed Buchwald (47:48.400)
things like that. But if they're working properly, you get the actual qualities of the world.
Jed Buchwald (47:55.440)
Now, that break, which is occurring towards the end of the 16th century and is most visible in
Jed Buchwald (48:02.960)
Descartes, is the break between conceiving that the qualities of the world are very different
Jed Buchwald (48:12.160)
from the qualities that we perceive. That in fact, the qualities of the world consist almost
Jed Buchwald (48:17.920)
entirely in shapes of various kinds and maybe hard particles or whatever, but not colors,
Jed Buchwald (48:28.640)
not sounds, not smells, not softness and hardness. They're not in the world, they're in us.
Jed Buchwald (48:37.840)
That break Newton is picking up as he reads Descartes. He's going to disagree with a lot in
Jed Buchwald (48:43.280)
Descartes, but that break he is, among other things, picking up very strongly. And that
Jed Buchwald (48:50.800)
underlies a lot of the way he works later on when he becomes skeptical of the evidence provided
Jed Buchwald (48:58.080)
by the senses. Yeah, that's actually, I don't know, the way you're describing is so powerful.
Jed Buchwald (49:05.040)
It just makes me realize how liberating that is as a scientist, as somebody who's trying
Jed Buchwald (49:11.920)
to understand reality, that our senses are not to be trusted, that reality is to be investigated
Jed Buchwald (49:24.480)
through tools that are beyond our senses. Yes, or that improve our senses in some ways.
Jed Buchwald (49:34.320)
That's pretty powerful. For a human being to realize I can't trust my own senses at that time,
Jed Buchwald (49:49.680)
that's pretty trippy. It's coming in, it's coming in. And I think it arises probably a fair number
Jed Buchwald (49:59.040)
of decades before that, perhaps in part with all chemical experimentation and manipulations,
Jed Buchwald (50:05.520)
that you have to go through elaborate structures to produce things and ways you think about it.
Lex Fridman (50:13.280)
But let me give you an example that I think you might find interesting because it's from
Jed Buchwald (50:17.680)
it involves that guy named Hooke that Newton had an argument with. And he had lots of arguments
Jed Buchwald (50:24.640)
with Hooke, although Hooke was a very clever guy and gave him some things that stimulated him later.
Jed Buchwald (50:30.400)
Anyway, Hooke, who was argumentative, and he really was convinced that the only way to gain
Jed Buchwald (50:38.720)
real knowledge of nature is through carefully constructed devices. And he was an expert
Jed Buchwald (50:48.080)
mechanic, if you will, at building such things. Now, there was a rather wealthy man in Danzig
Jed Buchwald (51:00.320)
by the name of Hevelius, Latinized name. He was a brewer in town. And he had become very
Jed Buchwald (51:06.720)
fascinated with the telescope. This is 30 years or so, 20 or 30 years after the telescope had
Jed Buchwald (51:14.720)
moved out and become more common. And he built a large observatory on the top of his brewery,
Jed Buchwald (51:21.920)
actually. And working with his wife, they used these very elaborately constructed
Jed Buchwald (51:32.080)
grass and metal instruments to make observations of positions of the stars. And he published a whole
Jed Buchwald (51:37.600)
new catalog of where the stars are. And he claimed it was incredibly accurate. He claimed it was so
Jed Buchwald (51:45.120)
accurate that nothing had ever come close to it. Hooke reads this, and he says, wait a minute,
Jed Buchwald (51:51.120)
you didn't use a telescope here of any kind, because what's the point? Unless you do something
Jed Buchwald (51:56.960)
to the telescope, all you see are dots with stars. You just use your eyes. Your eyes can't be that
Jed Buchwald (52:02.480)
good. It's impossible. So what did Hooke do to prove this? He said, what you should have done
Jed Buchwald (52:08.000)
is you should have put a little device in the telescope that lets you measure distances between
Jed Buchwald (52:12.720)
these dots. You didn't do that. And because you didn't, there's no way you could have been that
Jed Buchwald (52:17.440)
good. At two successive meetings of the Royal Society, he hauls the members out into the courtyard
Lex Fridman (52:28.000)
and he takes a card and he makes successive black and white stripes on the card. And he pastes the
Jed Buchwald (52:34.960)
card up on a wall and he takes them one by one. He says, now move back looking at it, presumably
Jed Buchwald (52:42.080)
with one eye, until you can't tell the black ones from the white stripes. He says, that I can then
Jed Buchwald (52:48.960)
measure the distance. I can see the angles. I can give a number then for what is the best possible,
Lex Fridman (52:57.360)
what we would call perceptual acuity of human vision. And it turned out, he thought, to be
Jed Buchwald (53:05.280)
something like 10 or more times worse than this guy Hevelius had claimed. So obviously he says,
Jed Buchwald (53:12.560)
Hooke, Hevelius. Well, years ago, I calculated Hevelius's numbers and so on using modern
Jed Buchwald (53:22.080)
tables from NASA and so on. And they are even more accurate than Hevelius claimed. And worse than
Jed Buchwald (53:28.000)
that, the Royal Society sent a young astronomer named Halley over to Dantzig to work with him.
Lex Fridman (53:35.600)
And Halley writes back and he says, I couldn't believe it, but he taught me how to do it.
Lex Fridman (53:41.120)
And I could get just as good as he. How is it possible? Well, here, this shows you something
Jed Buchwald (53:46.080)
very interesting about experiments, perception and everything else. Hooke was right, but he was also
Jed Buchwald (53:52.400)
wrong. He was wrong for the right reasons and he was right for the wrong reasons. And what do I
Jed Buchwald (53:59.200)
mean by that? What he actually found was the number for what we now call 2020 vision. He was
Jed Buchwald (54:09.040)
right. You can't tell, except a few people, much better than that. But he was observing the wrong
Jed Buchwald (54:16.960)
thing. What Hevelius was observing was a bright dot, a star, moving past a pointer.
Jed Buchwald (54:28.240)
Our eyes are rather similar to frogs eyes. You know, I'm sure you've heard the story. If I hold
Jed Buchwald (54:34.960)
a dead fly on a string in front of a frog and don't move it, the frog pays no attention. As soon
Jed Buchwald (54:41.360)
as I move the fly, the frog immediately tongue lats out because the visual system of the frog
Jed Buchwald (54:48.960)
responds to motion. So does ours and our acuity for distinguishing motion from statics, five or
Jed Buchwald (54:58.160)
more times better. Yeah, that's fascinating. Damn. And of course, I mean, maybe you can comment on
Jed Buchwald (55:06.240)
their understanding of the human perceptual system at the time. It's probably really terrible.
Jed Buchwald (55:12.080)
Like, yeah, like I've recently been working with just almost as a fun side thing with vision
Jed Buchwald (55:16.800)
scientists and peripheral vision. It's a, it's a beautiful, complex mess. That whole thing,
Jed Buchwald (55:23.200)
we still don't understand all the weird ways that human perception works. And they were probably
Jed Buchwald (55:29.120)
terrible at it. They probably didn't even have any conceptual peripheral vision or anything like
Jed Buchwald (55:34.400)
any conceptual peripheral vision or, or the fovea or, or, I mean, basically anything.
Jed Buchwald (55:41.680)
They had some, I mean, because actually it was Newton himself who probed a lot of this. For
Jed Buchwald (55:46.320)
instance, Newton, the young Newton trying to work his way around what's going on with colors,
Jed Buchwald (55:53.920)
wanted to try and distinguish colors that occur through natural processes out there and colors
Jed Buchwald (56:01.440)
that are a result of our eyes not operating whites. You know what he did? It's a famous thing.
Jed Buchwald (56:06.960)
He took a stick and he stuck that stick under his lower eyelid and pushed up on his eyeball.
Lex Fridman (56:14.640)
And what that did, what produced colored circles at diametrically opposite positions of the stick
Jed Buchwald (56:22.960)
in the eyeball. And he moved it around to see how they moved, trying to distinguish.
Lex Fridman (56:27.600)
Legit. Right? I always have to tell my students don't do this, but.
Jed Buchwald (56:34.320)
Or do it if you want to be great and remembered by human history. That's, there's a lot of
Jed Buchwald (56:40.960)
equivalent to sticking a stick into your eye in modern day that may pay off in the end. Okay.
Lex Fridman (56:51.360)
As a small aside, is the Newton and the Apple story true?
Lex Fridman (56:55.120)
No. Was it a different fruit?
Jed Buchwald (57:00.240)
As a colleague of mine named Simon Schaffer in England once said on a Nova program that we were
Jed Buchwald (57:06.560)
both on, the role of fruit in the history of science has been vastly exaggerated.
Jed Buchwald (57:13.920)
Okay. So was there any, I mean, to, to the zoom out moments of epiphany,
Jed Buchwald (57:19.840)
is, is there something to moments of epiphany? Oh, again, this is the paradigm shift versus the
Jed Buchwald (57:24.480)
gradualism. There is a shift. It's a much more complex one than that. And we,
Jed Buchwald (57:33.920)
as it happens, a colleague of mine and I are writing a paper right now on one of the aspects
Jed Buchwald (57:39.040)
of these things based on the work that many of our colleagues have done over the last 30 and 40 years.
Jed Buchwald (57:44.960)
Let me try and see if I could put it to you this way. Newton, until the early 1670s and probably
Jed Buchwald (57:56.320)
really until a fair time after that, first of all, was not very interested in questions of motion.
Jed Buchwald (58:03.680)
He was working actually in all chemical relationships or what is called by historians
Jed Buchwald (58:09.360)
chymistry, a kind of early modern chemical structure. Colleagues of ours at Indiana have
Jed Buchwald (58:15.600)
even reproduced the amalgams that, you know, anyway, his way of thinking about motion involved
Jed Buchwald (58:23.680)
a certain set of relationships, which was not conducive to any application of motion.
Jed Buchwald (58:35.120)
Not conducive to any application that would yield computationally direct results for things like
Jed Buchwald (58:46.000)
planetary motions, which he wasn't terribly interested in anyway. He enters a correspondence
Jed Buchwald (58:54.720)
with his original nemesis, Robert Hooke. And Hooke says, well, have you ever thought about,
Lex Fridman (59:00.560)
and then Hooke tells him a certain way you might think about it. And when Newton hears that,
Jed Buchwald (59:06.800)
he recognizes that there is a way to inject time that would enable him to solve certain problems.
Jed Buchwald (59:14.240)
It's not that there was anything he thought before that was contrary to that way of thinking,
Lex Fridman (59:21.520)
it's just that that particular technical insight was not something that,
Jed Buchwald (59:28.160)
for a lot of reasons that are complex, had never occurred to him at all. And that sent him a
Jed Buchwald (59:34.560)
different way of thinking. But to answer your question about the Apple business, which is always
Jed Buchwald (59:39.760)
about, you know, gravity and the moon and all of that being, no. The reason there is that the idea
Jed Buchwald (59:48.000)
that what goes on here in the neighborhood of the earth and what goes on at the moon,
Jed Buchwald (59:55.760)
at the moon, let us say, remind the sun and the planets, can be due to a direct relationship
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