.@krysboydthink: You disagree with the notion, made popular by Stephen Hawking and others, that free will is, in fact, a sort of illusion. Can you talk about that? @DavidDeutschOxf: Yes, this is the idea that because we are made of atoms, and atoms are subject to laws of motion that don't allow any wiggle room, therefore everything we do also doesn't allow any wiggle room, and therefore our free will must be an illusion. Now, I think that's called reductionism, and it is simply a mistake. It's sort of assuming that the laws of physics are a kind of a person; they're a kind of a supernatural being that makes us do things, but it's not true. The laws of physics are simply a description of what we do. It's not the laws of physics that make atoms move around; laws of physics are simply a description of what they do. The thing about what we see about the world is that there are levels of description: there are descriptions at the atomic level and descriptions at the molecular level and the biological level, and then there are descriptions and explanations at the level of human thought. There's no reason to expect that just because there's a low-level description, there isn't also a high-level explanation and description. In the book [The Beginning of Infinity], I give some arguments, both due to me and due to people like Douglas Hofstadter, that the high-level description is sometimes the only reasonable explanation of what is happening. So, for example, if you play a game of chess against a computer, then it's not the silicon that has beaten you; it's the program. The program in the computer, and that program, is an abstraction. The program doesn't consist of atoms; the program is an abstraction over the atoms, just like human thought is an abstraction over our atoms. It is the programs that have beaten you. When I make a decision, it's I who have made it, not my atoms and not the laws of physics. @krysboydthink: So, we get really unnecessarily and detrimentally hung up on this sense that we can get to the absolute foundation of anything. @DavidDeutschOxf: That's true as well. The idea that there's an absolute foundation is a formula for stagnation in science and for tyranny in politics and so on. There will never be an absolute foundation for knowledge because there will always be the question, once we have got a particular fundamental theory, of why it is that way and not some other way.

.@DavidDeutschOxf: "A particular theory is either true or false. There's no probability about it, or bits of it, you know; each bit of it is either true or false. Again, there's no probability about it. So what we should be saying is, we have explained this phenomenon better than it was explained before. We might be wrong, but if we are wrong, then what we expect is that the way in which we are wrong will not be the old theory. Even in some cases, when we revert to what looks like the old theory, it still isn't quite the old theory. This happened several times in a row with the question of whether light is a wave or a particle. So, light in everyday experience seems to be continuous. When physicists started investigating it, like Newton, for instance, they thought that it must be composed of particles because the idea of the continuum didn't make sense with it moving. And then later, that was refuted apparently by interference phenomena, and then it was found to be particles again. And then the initial quantum theory said it's both particles and waves at the same time, which is nonsense. And now we know that it's a wave in the multiverse that manifests as particles in particular universes. So, that's the current theory. So, I don't know how many that is—that's half a dozen changes. In no case, although we went from particles to waves to particles and so on, is it the case that we went back to the previous theory. We just went back to that aspect of the previous theory. So, each of those steps was an objective improvement, even though the headline was back and forth. The full theory was continuous improvement."