2021-06-13 ToKCast Question for David 2
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Duration: 00:14:58
Transcript
Brett Hall
Popper solved the so-called problem of induction. That was the problem of how, if mathematics or logic or pure reason can be certain of the truth of its conclusions it can’t by the way, but on the assumption it can then how does science work to generate truths about the universe for us? After all, it can’t be like mathematics where you just begin with axioms you are absolutely certain of and derive conclusions that you’re absolutely certain of. The whole point of science is to go out into the world and investigate what is absolutely true on this view. So, it is said, surely it’s a process of repeated observation and presuming the more observations you repeatedly see the more certain or closer to true or confident you can become. But the problem is how then can we be justified in thinking we are close to truth or closer to truth with these repeated observations? It was the philosopher David Hume who raised this so-called problem of induction in the 18th century and philosophers still bizarrely today worry about it. That worry being, how can we be justified given our repeated set of observations say that the sun has always risen in the past that we can conclude it is true to say it will therefore rise tomorrow? I say it’s bizarre because the problem has been solved and basically it’s not a problem at all. Repeated observations is not what science is about nor ever has been about. Popper first best addressed this and solved it. In many places including, for example, his first book, The Logic of Scientific Discovery but the most succinct explanation that I’ve found, my favourite one, is here in this book, Objective Knowledge. It’s right there in Chapter One. It refutes inductivism and justificationism. It refutes therefore the modern incarnations of this kind of inductivist view of the world which is called Bayesian epistemology or just Bayesianism. That’s an old idea, rather like creationism which these days goes by the repackaged name Intelligent Design or Marxism which is now repackaged to be called Socialism or even in some moods, Wokeism. It’s all the same similar set of misconceptions just being repackaged and rebranded. And so here we have inductivism being called Bayesianism. But the problem with inductivism or Bayesianism is that in science, like elsewhere in fact, we are not actually after justifications that our predictions will continue off into the infinite future or that they probably will. What science is about on Popper’s view are testable theories. But not only that. He is keenly interested in explanations. And that word explanation comes up again and again in his work. There’s a chapter in here titled The Aim of Science. And in it Popper says explicitly on the first page of that chapter in fact and I’ll quote, Popper writes, I suggest that it is the aim of science to find satisfactory explanations of whatever strikes us as being in need of an explanation. By an explanation or a causal explanation is meant a set of statements by which one describes the state of affairs to be explained while the others, the explanatory statements, form the explanation in the narrowest sense of the word. And so he goes on for an entire chapter and throughout this book about explanations.
Brett Hall
Popper was not only about testability. In The Fabric of Reality, David Deutsch sharpens this up still further and clarifies what Popper has said. Any crank with a prophecy about how the world will end next Tuesday has an experimentally testable, falsifiable theory. But that’s not enough. That is not Popperian. Despite what prominent scientists and philosophers say about Popper, Popper’s philosophy is not primarily about falsification. Any more than Einstein’s physics is about the speed of light. Yes, falsification is an important element of Popper’s philosophy. And the speed of light is a crucial component of Einstein’s relativity theories. But to think that is all and everything is wrong. To think that knowing the fact that the speed of light is constant gives you anything like a deep understanding of special, let alone general, relativity is clearly misconceived. So to think falsification is all and only what Popperian epistemology reduces to is approximately the same level of error. It doesn’t take this many pages to say scientific hypotheses should be testable. Or all of these other books either. What David explains here in The Fabric of Reality is that the entire content of a scientific theory is in the explanation, not merely the testable predictions. For example, and this is from The Fabric of Reality, a random person who claims eating one kilogram of grass cures your common cold has a testable theory. But you should not test it. No one should. No one will. You can reject it on the basis it is explanationless. There’s no explanation accompanying that prediction. Eat the one kilogram of grass and your common cold will be cured. For more on that, read the book or listen to my podcast with Naval that you can find here. Hence, some of the additional work that David has done here. Unlike other popular science books that you might see behind me or other popular books about science or related matters like religion written by scientists, we find something different in The Beginning of Infinity. It seems to me new discoveries being explained. It’s not merely a summary of our existing knowledge, even our existing cutting edge knowledge. As exciting as that all might be, but rather it contains some new contributions to epistemology. How knowledge works. As I said to David about this when we spoke, the first time this seems to crop up actually is in chapter one, the Reach of Explanations. And there we get the concept of good explanations. Good explanations being actual explanations that account for what is out there in the world and how it works that are hard to vary. These hard to vary explanations. Now I’m convinced and most people who hear about it become convinced over time. But I think there’s a lot of people who think, well, science, isn’t it just about testable theories?
Brett Hall
Why isn’t testable theories enough?
David Deutsch
So there was a lot about explanations even in my first book. And some careful readers pointed out that I’d never actually explained what an explanation is in the fabric of reality. In fact, I seem to have taken a bit of a cop out path by just saying about explanations that there isn’t any closed list of attributes that an explanation must have. And that’s because it seemed to me that and I think it does seem to many people that the difference between an explanation and a prediction is obvious. But to most people, it was quite opaque. So I thought about it. And this is indeed one of the few things that I will acknowledge is kind of a bit of an innovation in The Beginning of Infinity. I thought about what exactly makes the difference. And I thought of some examples such as the explanation of the seasons as opposed to predicting them. And then I think that the example that I like best, although again, not everyone does, is the example of the conjurer. Yes. Where you go in and you go in to see this conjuring performance and you see some cups and balls and the conjurer puts the ball under the cup. And after a while you begin to predict that the cup where he puts the ball under is not going to be the one where it ends up.
Brett Hall
But that doesn’t mean you can explain what’s going on in the trick.
David Deutsch
Yeah, exactly. So you can predict quite confidently that the ball isn’t there. And there you are. It’s vindicated. But that’s not what you mean by how is the trick done. What you mean is what has happened to bring about the thing you saw. And so you’re not asking for an account of the thing you saw, even a perfect prediction of the thing you saw. You’re asking about the thing you didn’t see.
Brett Hall
Yes, yes. And this comes up so often throughout the book, really. And I think it’s a subtle point, easily missed. And of course, the other example that you use and that you often go to is this idea of dinosaurs. The one thing that you actually can’t observe is indeed the one thing that you’re invoking as actually existing and causing the phenomena that you do observe.
David Deutsch
Quite so. And in all these cases, that unobserved thing is the thing that you’re really interested in. It’s the only reason you’re interested in any kind of prediction at all.
Brett Hall
Yes. And now this concept of then hard to vary, where all the parts of the explanation have some functional role. And this is really what makes the explanation a good explanation as opposed to any arbitrary account that could be easily varied, mythological accounts and so on, magical accounts. Did that come to you? Did you have that in mind during the Fabric of Reality writing it then or did it only come later in light of people saying, you know, can you sharpen up what you mean by explanation?
David Deutsch
It’s the latter. Like I said, while I was writing Fabric of Reality, I kind of thought, rather foolishly, that these were words that had an uncontroversial meaning. And it didn’t occur to me that most people would not have this meaning in mind, although many people did. So in that sense, it wasn’t something I invented. It was something that I realized needs to be elaborated, to be written down more clearly. And then I started to think about, well, things that are explanations and things that aren’t explanations and like the ancient myths and so on. And then I thought with the conjurer, there are circumstances where the conjurer did it is the explanation that the person wants. You can imagine a person who believes in magic and is sort of slowly coming out of that state of mind, like James Randi’s famous story when he was a teenager and when he first exposed a fake psychic and was horrified to find that most of the people in the audience didn’t want to know the truth. Right. Yeah. That happened more than once.
Brett Hall
There was a famous I don’t know if you know the famous story that he was on Australian television. He did the same to the spoon bender, Yuri Geller, on one of our daytime lunchtime talkback television shows. And the audience was very upset with him. And indeed, the host was as well and stormed off the set. Did the same thing to Randi. Wow. Right. It’s about all this stuff that you’re going to prove. You go against the lady like Doris Stokes who never harmed anybody in her whole life and you call her a charlatan and a fake. You know a great deal about it. Yes, I do. You said that she was a liar on the radio. You called her a liar. No. And that woman wouldn’t lie to anybody. And I don’t know whether she’s right or wrong. I would. She wouldn’t lie to anybody. We’re going for a commercial break and you can piss off.
David Deutsch
So there you have it. I mean, that anger would happen, I suppose, whether or not he revealed how he did it. It was the fact that he was revealing that he did do it that was the thing that angered them. And that was the relevant explanation in context. So that’s why I have to say it’s an explanation is hard to vary while still solving the problem that it purports to solve. Yes. Which might be different for different people as well in the same situation.
Brett Hall
Different for different people in the same situation. This implies that problems are parochial, which means they are in a time and a place. They don’t exist forever in all places and always. Often the highly parochial nature of a problem situation is very specific for a certain individual. What works for you might not work for me. Medicine is a great example of this. Some treatments work for some people, but not for others, even if they are very similar people with the same disease. But good explanations are not just about science. Science just happens to be a neat and relatively clean and easy way to speak about this whole area of epistemology. It is especially when we consider the physical sciences and physics in particular, when compared to so many other areas, because in science, in physics, it is highly precise and rich with actual knowledge. And of course, we can do experiments, especially crucial experiments. We can more easily compare competing theories, although indeed we rarely have competing theories. So we can actually notice when there exists a good explanation and when there does not. But the concept of good, hard to vary explanations, reaches into all areas that we are interested in. History, art, morality, psychology, meditation practice, business, economics, philosophy, and of course, one’s own personal life. It’s rather often we lack good explanations. But this is of course the point. We should be seeking them. Happily we can because problems are soluble. And we are, all of us, creative. That is our defining characteristic after all. Thank you.
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