“If you think about things that happen, as being computations... a computation in the sense that it has definite rules... You follow them many steps and you get some result. ...If you look at all these different computations that can happen, whether... in the natural world... in our brains... in our mathematics, whatever else, the big question is how do these computations compare. ...Are there dumb ...and smart computations, or are they somehow all equivalent? ...[T]he thing that I ...was ...surprised to realize from ...experiments ...in the early 90s, and now we have tons more evidence for ...[is] this ...principle of computational equivalence, which basically says that when one of these computations ...doesn't seem like it's doing something obviously simple, then it has reached this ...equivalent layer of computational sophistication of everything. So what does that mean? ...You might say that ...I'm studying this tiny little program ...and my brain is surely much smarter ...I'm going to be able to systematically outrun [it] because I have a more sophisticated computation ...but ...the principle ...says ...that doesn't work. Our brains are doing computations that are exactly equivalent to the kinds of computations that are being done in all these other sorts of systems. ...It means that we can't systematically outrun these systems. These systems are computationally irreducible in the sense that there's no ...shortcut ...that jumps to the answer.”

“The thing I've seen about people on the computer and the Internet is that it's addicting. We told him not to get on it, and you turn around and he's on the computer.”

“If you look at the history of big obstacles in understanding our world, there's usually an intuitive assumption underlying them that's wrong. In the case of the Solar System it was intuitively obvious that the Earth was at the center of the Solar System and things moved around us, but that just turned out to be wrong. … And it intuitively seems correct that the brain is just some sort of computer—it just seems natural. … But it has undermined almost all of our work to build intelligent machines and understand thinking. It's just wrong … the brain isn't like a computer at all.”

“Quantum mechanics is weird. I don't understand it. Just live with it. You don't have to understand the nature of things in order to build cool devices…If you can figure out how to take advantage of this quantum multitasking, we can build computers that can do computations that no classical computer could do even if it were the size of the entire universe.”

“If you compute the years in which all this has happened, it is but a little while; if you number the vicissitudes, it seems an age.”
Si computes annos, exiguum tempus, si vices rerum, aevum putes.

“I talk to myself through the computer. I ask myself questions, leave things to be looked at again, things that you would do with a notepad. It turns out today that it’s much better today to do with a personal computer rather than a notepad.”

“[Computer science] is not really about computers -- and it's not about computers in the same sense that physics is not really about particle accelerators, and biology is not about microscopes and Petri dishes…and geometry isn't really about using surveying instruments. Now the reason that we think computer science is about computers is pretty much the same reason that the Egyptians thought geometry was about surveying instruments: when some field is just getting started and you don't really understand it very well, it's very easy to confuse the essence of what you're doing with the tools that you use.”

“Emails in general are terrible. There's no security. It happens so often. I'm old-fashioned. I put a letter in an envelope and have it hand delivered. My son is 10 years old, and he has grown up computer literate. They start using computers before they can walk. His computer was locked and he unlocked it. And I said, ‘Barron, how did you do that?”

“Ford carried on counting quietly. This is about the most aggressive thing you can do to a computer, the equivalent of going up to a human being and saying "Blood… blood… blood… blood…”

“A wonderful thing about a book, in contrast to a computer screen, is that you can take it to bed with you.”