"There's a notorious problem with defining information within physics, namely that on the one hand information is purely abstract, and the original theory of computation as developed by Alan Turing and others regarded computers and the information they manipulate purely abstractly as mathematical objects. Many mathematicians to this day don't realize that information is physical and that there is no such thing as an abstract computer. Only a physical object can compute things."
"I think it's important to regard science not as an enterprise for the purpose of making predictions, but as an enterprise for the purpose of discovering what the world is really like, what is really there, how it behaves and why."
"Think about it this way: previously we thought that our universe was like a spherical balloon. In the new picture, it's like a balloon producing balloons, producing balloons. This is a big fractal. The Greeks were thinking about our universe as an ideal sphere, because this was the best image they had at their disposal. The 20th century idea is a fractal, the beauty of a fractal. Now, you have these fractals. We ask, how many different types of these elements of fractals are there, which are irreducible to each other? And the number will be exponentially large, and in the simplest models it is about 10 to the degree 10, to the degree 10, to the degree 7. It actually may be much more than that, even though nobody can see all of these universes at once."
"I seem to be saying two things that contradict each other. On the one hand, we trust scientific knowledge, on the other hand, we are always ready to modify in-depth part of our conceptual structure about the world. But there is no contradiction, because the idea of a contradiction comes from what I see as the deepest misunderstanding about science: the idea that science is about certainty."
"Andrei Linde had some ideas, Alan Guth had some ideas, Alex Vilenkin had some ideas. I thought I was coming in with this radically new idea that we shouldn't think of the universe as existing on this global scale that no one observer can actually see, that it's actually important to think about what can happen in the causally connected region to one observer, what can you do in any experiment that doesn't actually conflict with the laws of physics, and require superluminal propagation, that we have to ask questions in a way that conform to the laws of physics if we want to get sensible answers."
"The question is, as a scientist, can we take these ideas and do what we did in biology, at least based on networks and other ideas, and put this into a quantitative, mathematizable, predictive theory, so that we can understand the birth and death of companies, how that stimulates the economy?"
"Inflation does not provide a natural explanation for why the early universe looks like it does unless you can give me an answer for why inflation ever started in the first place. That is not a question we know the answer to right now. That is why we need to go back before inflation into before the Big Bang, into a different part of the universe to understand why inflation happened versus something else. There you get into branes and the cyclic universe. ... I really don't like any of the models that are on the market right now. We really need to think harder about what the universe should look like."
"We have decided, as a scientific endeavor, to extrapolate as much as we can from our knowledge of the individual processes that we can measure: evaporation from the ocean, the formation of a cloud, rainfall coming from a cloud, changes in wind patterns as a function of the pressure field, changes in the jet stream. What we have tried to do is encapsulate those small-scale processes, put them together, and see if we can predict the emerging properties of that fundamental complex system."
"Science is the greatest achievement of human history so far. I say that as a huge admirer of the Renaissance and Renaissance art, music and literature, but the world-transforming power of science and the tremendous insights that we've gained show that this is an enterprise, a wonderful collective enterprise, that is a great achievement of humanity. How are we going to make more people party to that? That's a pressing question for our century."
"In a very pure sense you build the accelerator you need when you know what the question is."
"Warming is unequivocal, that's true. But that's not a sophisticated question. A much more sophisticated question is how much of the climate Ma Earth, a perverse lady, gives us is from her, and how much is caused by us. That's a much more sophisticated, and much more difficult question."