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OUTLINE:
0:00 - Introduction
0:31 - How does science progress?
16:44 - Theory of Everything
28:37 - Consciousness 
32:12 - Most Beautiful Moments in Science
39:57 - Isaac Newton
1:06:10 - Competition in Science
1:16:44 - Newton's Career
1:29:55 - Importance of Data
1:36:13 - Alchemy
1:40:28 - Newton and Religion
1:43:41 - Showing Newton the future
1:48:25 - Newton and Einstein

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The following is a conversation with Jed Buchwald, a professor of history and a philosopher of science at Caltech, interested especially in the development of scientific concepts and the instruments used to create and explore new effects and ideas in science.

To support this podcast, please check out our sponsors in the description.

This is the Lex Friedman Podcast, and here is my conversation with Jed Buchwald.

Does science progress via paradigm shifts and revolutions as philosopher Thomas Kuhn said, or does it progress gradually?

Well, I got into this field because I was Tom Kuhn's research assistant 50 years ago, 52 years ago.

He pulled me into it out of physics instead.

In the years when I was at MIT running an institute, he was then in the philosophy department, used to come over all the time to the talks we held and so on.

He, of course, developed his ideas a lot over the years.

The thing that he's famous for, the structure of Scientific Revolutions, came out in

And as you just said, it offered an outline for what he called a paradigmatic structure, namely the notion that you have to look at what scientists do as forming a community of investigators, and that they're trying to solve various puzzles, as he would put it, that crop up, figuring out how this works, how that works, and so on.

And of course, They don't do it out of the blue, they do it within a certain framework.

His notion was that eventually they run into troubles or what he called anomalies, that kind of cracks things.

Somebody new comes along with a different way of doing it, et cetera.

Tom and I used to have lengthy discussions about that over the years.

I do think there is a common structure that formulates both theoretical and experimental practices.

And historians nowadays of science like to refer to scientific work as what scientists practice.

And I can give you all kinds of examples of that.

I once wrote a book on the origins of wave theory of light, and that is 1 of the paradigmatic examples that Tom used, only it didn't work that way exactly, because he thought that what happened was that the wave theory ran into trouble with a certain phenomenon which it couldn't crack.

Well, it turned out that in fact historically that phenomenon was actually not relevant later on to the wave theory.

And when the wave theory came in, the alternative to it which had prevailed, which was Newton's views, light is particles, that it seemed couldn't explain what the wave theory could explain.

The wave theory offered the opportunity to deploy novel experimental and mathematical structures which gave younger scientists, mathematicians and others, the opportunity to effect, manufacture, make new sorts of devices.

It's not that the alternative couldn't sort of explain these things, but it never was able to generate them de novo as novelties.

In other words, if you think of it as something scientists wanna progress in the sense of finding new stuff to solve, then I think what often happens is, is that it's not so much that the prevailing view can't crack something as that it doesn't give you the opportunity to do new stuff.

When you say new stuff, are we referring to experimental science here or new stuff in the space of new theories?

So how does that, can you maybe elaborate a

The prevailing view of light, at least in France where the wave theory really first took off, although it had been introduced in England by Thomas Young, The prevailing theory dates back to Newton, that light is a stream of particles and that refraction and reflection involve sort of repulsive and attractive forces that deflect and bend the paths of these particles.

Newton was not able successfully to deal with the phenomenon of what happens when light goes past a knife's edge or a sharp edge, what we now call diffraction.

He had cooked up something about it that no mathematical structure could be applied.

Thomas Young first, but really this guy named Augustin Fresnel in France, deployed, In Fresnel's case, rather advanced calculus forms of mathematics which enabled computations to be done and observations to be melded with these computations in a way that you could not do or see how to do with Newton.

Did that mean that the Newtonian explanation of what goes on in diffraction fails?

You can actually make it work, but you can't generate anything new out of it.

Whereas using the mathematics of wave optics in respect to a particular phenomenon called polarization, which ironically was discovered by partisans of Newton's way of doing things, you were able to generate devices which reflect light and crystals, do various things that the Newtonian way could accommodate only after the fact.

They couldn't generate it from the beginning.

And so if you want to be somebody who is working a novel vein, which increasingly becomes the case with people who become what we now call physicists in the 1820s, 30s, and 40s in particular, then that's the direction you're gonna go.

I wanna try to elaborate on the nature of the disagreement you have with Thomas Kuhn.

So do you still believe in paradigm shifts?

Do you still see that there's ideas that really have a transformational effect on science?

The nature of the disagreement has to do with how those paradigm shifts come to be?

How strong they may be at any given time is maybe not quite as powerful as Tom thought in general, although towards the end of his life, he was beginning to develop different modifications of his original way of thinking.

But I don't think that the changes happened quite so neatly, if you will, in reaction to novel experimental observations.

In terms of neatness, how much of science progresses by individual lone geniuses and how much by the messy collaboration of competing and cooperating humans?

I don't think you can cut that with a knife to say it's this percent and that percent.

It's almost always the case that there are 1 or 2 or maybe 3 individuals who are sort of central to what goes on when things begin to shift.

Are they inevitably and solely responsible for what then begins to happen in a major way?

You can go very far back with this, even into antiquity to see what goes on.

The major locus we always talk about from the beginning is if you're talking about Galileo's work on motion, for example, were there ways of accommodating it that others could adapt to without buying into the whole scheme?

Did it eventually evolve and start convincing people because you could also do other things with it that you couldn't otherwise do?

The great French mathematician, philosopher Descartes, who was a mechanical philosopher, he believed the world was matter in motion.

He never thought much of what Galileo had done in respect to motion because he thought, well, at best it's some sort of approximative scheme or something like that.

But 1 of his initial, I wouldn't call him a disciple, but follower who then broke with him in a number of ways, was a man named Christian Huygens, who was along with Newton, 1 of the 2 greatest scientists of the 17th century.

And Huygens nicely deployed Galilean relationships in respect to motion to develop all sorts of things, including the first pendulum-governed clock, and even figured out how to build 1 which keeps perfect time, except it didn't work, but he had the mathematical structure for it.

So is this should like, Yeah, can you define should?

Should means this, if you had taken up to a second year of physics courses, you would have heard his name because 1 of the fundamental principles in optics is called Huygens principle.

Yeah, so I have and I have heard his name.

So I mean, there's a very different thing between names attached to principles and laws and so on that you sometimes let go of, you just remember the equations of the principles themselves and the personalities of science.

And there's certain personalities, certain human beings that stand out.

And that's why there's a sense to which the lone inventor, the lone scientist is the way I personally, I mean, I think a lot of people think about the history of science, is these lone geniuses.

Without them, the sense is, if you remove Newton from the picture, if you remove Galileo from the picture, then science would, there's almost a feeling like it would just have stopped there.

Or at the very least, there's a feeling like it would take much longer to develop the things that were developed.

Is that a silly way to look at the history of science.

That's not entirely incorrect, I suppose.

I find it difficult to believe that had Galileo not existed, that eventually someone like Huygens, for instance, given the context of the time, what was floating around in the belief structure concerning the nature of the world and so on, the developments in mathematics and whatnot, that sooner or later, whether it would have been exactly the same or not, I cannot say, but would things have evolved?

If we look at the long arc of history of science, from back when we were in the caves trying to knock 2 rocks together, or maybe make a basic tool,

a long time from now, many centuries from now when human civilization finally destroys itself.

If we look at that history, and imagine you're a historian at the end, like with the fire of the apocalypse coming upon us, and you look back at this time in the 21st century, how far along are we on that arc?

Have we invented and discovered everything that's to be discovered, or are we at like below 1%?

You're gonna get a lot of absurd questions today.

It's a lugubrious picture you're painting there.

I don't even know what the word lugubrious

Well, let me try and separate the question of whether we're all going to die in an apocalypse in several hundred years or not from the question of where science may be sitting.

And I find it hard to say because in the deepest sense of the term, as it's usually deployed by philosophers of science today.

That is to say, I think our access to the inner workings of nature is inevitably mediated by what we can do with the materials and factors around us.

Does that mean that I don't think that the standard model in quantum electrodynamics is in, of course not.

I wouldn't even dream of saying such a thing.

It can do a lot, especially when it comes to figuring out what's happening in very large, expensive particle accelerators.

And applying results in cosmology and so on as well.

Do I think that we have inevitably probed the depths of reality through this?

I do not agree with Steven Weinberg, who thinks we have, about such things.

Do I, on the other hand, think that the way in which science has been moving for the last 100 years, physics in particular is what I have in mind, will continue on the same course.

In that sense, I don't, because we're not going to be building bigger and bigger and more and more expensive machines to rip apart particles in various ways.

In which case, what are physicists gonna do?

They'll turn their attention to other aspects.

There are all sorts of things we've never explained about the material world.

We don't have theories that go beyond a certain point for all sorts of things.

We can, can we for example, start with the standard model and work our way up all the way to chemical transformations?

You can make an argument about it and you can justify things, but that's in chemistry, that's not the way people work.

They work with much higher level quantum mechanical relationships and so on.

So this notion of the deep theory to explain everything is a longstanding belief, which goes back pretty far, although I think it only takes its fullest form sometime in towards the end of the 19th century.

You're referring to a hope, a dream, a reality of coming up with a theory of everything that explains everything.

So there's a very specific thing that that currently means in physics, is the unification of the laws of physics.

But I'm sure in antiquity or before, it meant maybe something else, or is it always about physics?

Because I mean, I think as you've kind of implied, in physics there's a sense, once you get to the theory of everything, you've understood everything.

But there's a very deep sense in which you've actually understood not very much at all.

You've understood at that particular level how things work, but you don't understand how the abstractions on top of abstractions form, all the way to the chemistry, to the human mind, and the human societies, and all those kinds of things.

So maybe you can speak to the theory of everything and its history and comment on what the heck does that even mean, a theory of everything.

Well, I don't think you can go back that far with something like that, maybe at best to the 17th century.

If you go back all the way in antiquity, there are of course discussions about the nature of the world.

But First of all, you have to recognize that the manipulative character of physics and chemistry, the probing of, let me put it this way.

We assume and have assumed for a long time, I'll come back to when in a moment, that if I take a little device which is really complicatedly made out of all kinds of things and I put a piece of some material in it, and I monkey around with it and do all kinds of unnatural things to it, things that wouldn't happen naturally, and I find out how it behaves and whatnot.

And then I try and make an argument about how that really applies even in the natural world without any artificial structures and so on.

That's not a belief that was widely held by pretty much anyone until sometime maybe in the 1500s.

And when it was first held, it was held by people we now call alchemists.

So alchemy was the first, the early days of the theory of everything, of a dream of a theory of everything.

I think it's more along the way a dream that by probing nature in artificially constructed ways, we can find out what's going on deep down there.

So that's distinct from science being an observing thing where you observe nature and you study nature.

You're talking about probing, like messing with nature to understand it.

Indeed I am, but that of course is the very essence of experimental science.

You have to manipulate nature to find out things about it, and then you have to convince others that you haven't so manipulated it that what you've done is to produce what amounts to fake, artifactual behavior that doesn't really hold purely naturally.

So where are we today in your sense to jump around a little bit with the theory of everything?

Maybe a quick kind of sense you have about the journey in the world of physics that we're taking towards the theory of everything.

Well, I'm of course not a practicing physicist.

I mean, I was trained in physics at Princeton a long time ago.

I was taking graduate courses in those days in general relativity.

I was an undergraduate, but I moved up and then I took a course with him.

Well, you made the mistake of being compelled by charismatic philosophers and never looked back.

And from what I understand, talking especially to my friends at Caltech, like Kip Thorne and others, the fundamental notion is that actually the laws that even at the deepest level we can sort of divine and work with in the universe that we inhabit are perhaps quite unique to this particular universe as it formed at the Big Bang.

If you are very mathematically inclined, the prevailing notion for several decades now has been what's called string theory, but that has not been able to figure a way to generate probative experimental evidence, although it's pretty good apparently at accommodating things.

And then the question is, what's before the Big Bang?

Or actually the word before doesn't mean anything given the nature of time, but why do we have the laws that prevail in our universe?

Well, there is a notion that those laws prevail in our universe because if they didn't, we wouldn't be here.

That's a bit of a cyclical, but nevertheless, a compelling definition.

And there's all kinds of things like the, it seems like the unification of those laws could be discovered by looking inside of a black hole, because you get both the general relativity and the quantum mechanics, quantum field theory in there.

Experimentally, of course, there's a lot of interesting ideas.

We can't really look close to the Big Bang, can't look that far back.

There's Caltech and MIT, LIGO, looking at gravitational waves, perhaps allows us to march backwards and so on.

And there's of course, the theory of everything, like with a lot of things in science, captivates the dreams of those who are perhaps completely outside of science.

It's the dream of discovering the key to the nature of how everything works.

That's perhaps the thing, the basic elements of what makes up a scientist in the end is that curiosity, that longing to understand.

Let me ask, you mentioned a disagreement with Weinberg on reality.

Well, obviously I don't disagree with Steve Weinberg on physics itself.

I wouldn't know enough to even begin to do that.

And clearly, he's 1 of the founders of the standard model and so on, and it works to a level of accuracy that no physical theory has ever worked at before.

I suppose the question in my mind is something that in 1 way could go back to the philosopher Immanuel Kant in the 18th century, namely, can we really ever convince ourselves that we have come to grips with something that is not in itself knowable to us by our senses or even except in the most remote way through the complex instruments that we make as to what it is that underlies everything.

Can we corral it with mathematics and experimental structures?

Do I think that a particular way of corralling nature will inevitably play itself out?

So the basic question is, can we know reality?

Is that the Kant question, Is that the Weinberg question?

Sounds like a very trippy question because a lot of it rests on definitions of no and comprehend and reality, but get to the bottom of it.

Like it's turtles on top of turtles, can we get to the bottom turtle?

Well, Maybe I can put it to you this way, in a way that I often begin discussions in a class on the history of science and so on, and say, I'm looking at you.

You are in fact a figment of my imagination.

If I were a dragonfly looking at you, whatever my nervous system would form by way of a perceptual structure would clearly be utterly different from what my brain and perceptual system altogether is forming when I look at you.

Well the dragonfly is certainly very impressive, so I don't know.

What is that supposed to tell us about objective reality?

Well, I think it means that it's very difficult to get beyond the constructs that our perceptual system is leading us to.

When we make apparatus and devices and so on, we're still making things, the results of which or the outputs of which we process perceptually in various ways.

And an analogy I like to use with students sometimes is this.

All right, they all have their laptops open in front of them, of course, okay?

And I say, okay, click on it and open it up.

He said, well, I'm looking at the paper that you sent me.

What you're looking at is a stream of light coming off LEDs or LCDs coming off a screen.

And I said, what happens when you use your mouse and move that fake piece of paper on the screen around?

You're not moving a piece of paper around, are you?

You're moving a construct around, a construct that's being processed so that our perceptual system can interact with it in the way we interact with pieces of paper.

So are there things outside of the reach of science?

Can you maybe, as an example, talk about consciousness?

I'm asking for a friend, trying to figure this thing out.

Well, boy, I mean, I read a fair bit about that, but I certainly can't really say much about it.

I'm a materialist in the deepest sense of the term.

I don't think there is anything out there except material structures which interact in various ways.

Do I think, for example, that this bottle of water is conscious?

It's an opinion, an educated opinion that may be very wrong.

Well, I know that you're conscious because I can interact directly with you.

Well, unless you're a figment of my imagination, of course.

No, or I'm a robot that's able to generate the illusion of consciousness effectively enough to facilitate a good conversation.

Because we humans do want to pretend that we're talking to other conscious beings because that's how we respect them.

If it's not conscious, we don't respect them.

Of course, we generalize from our own inner sense, which is the kind of thing Descartes said from the beginning.

We generalize from that, but I do think that consciousness must be something, whatever it is, that occurs as a result of some particular organizational structure of material elements.

Does materialism mean that it's all within the reach of science?

My sense would be that especially as neuroscience progresses more and more.

At Caltech, we just built a whole neuroscience arena and so on.

And as more knowledge is gained about the ways in which animals, when they behave, what patterns show up at various parts of the brain and nervous system, and perhaps extending it to humans eventually as well, we'll get more of a handle on what brain activity is associated with experiences that we have as humans.

Can we move from the brain activity to the experiences in terms of our, no, you can't.

Maybe the, Maybe consciousness is just 1 of the laws of physics that's yet to be discovered.

Maybe it's as simple as trying to plug it in and plug into the ability to generate and control that kind of law of physics that would crack open, where we would understand that the bottle of water is in fact conscious, just much less conscious than us humans, and then we would be able to then generate beings that are more conscious.

I'd have to stop drinking the water after that.

Every time you take a sip, there's a little bit of a suffering going on.

What to use the most interesting, beautiful moments in the history of science.

Well, I like to think of events that have a major impact and involve both beautiful conceptual, mathematical, if we're talking physical structures work, and are associated as well with probing experimental situations.

So among my favorites is 1 of the most famous, which was the young Isaac Newton's work with the colors produced when you pass sunlight through a prism.

It's not profoundly mathematical in 1 sense.

It needs the following though, which begins to show you, I think, a little bit about what gets involved when you've got a smart individual who's trying to monkey around with stuff and finds new things about it.

First let me say that the notion, the prevailing notion going back to antiquity was that colors are produced in a sense by modifying or tinting white light, that they're modifications of white light.

In other words, the colors are not in the sunlight in any way.

Now, what Newton did following experiments done by Descartes before him who came to very different conclusions, he took a prism.

You might ask, where do you get prisms in the 1660s?

They were pretty crude with bubbles in them and everything, but they produced colors so you could buy them at county fairs and things, very popular.

Oh, so they were modifying the white light to create colors.

Well, they were creating colors from it, well known.

He was by this time, even though he's very young, a very good mathematician.

And he could use the then known laws for how light behaves when it goes through glass to calculate what should happen if you took light from the sun, passed it from a hole, through a little hole, then hit the prism, goes out of the prism, strikes a wall a long distance away and makes a splash of light.

Never mind the colors for a moment, makes a splash of light there.

First of all, he abstracts from the colors themselves, even though that's what everybody's paying attention to initially.

Because what he knows is this, he knows that if you take this prism and you turn it to a certain particular angle that he knew what it should be because he could calculate things.

Very few other people in Europe at the time could calculate things like he could.

That if you turn the prism to that particular angle, then the sun, which is of course a circle, when its light passes through this little hole and then into the prism on the far distant wall should still make a circle, but it doesn't.

And this led him to a very different conception of light, indicating that there are different types of light in the sunlight.

Now to go beyond that, what's particularly interesting I think is the following.

When he published this paper, which got him into a controversy, He really didn't describe at all what he did.

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Jed Buchwald: Isaac Newton and the Philosophy of Science | Lex Fridman Podcast #214