During our interview Koch talked fast and jumped quickly from one big idea to the next. In a piece last week, "The Nature of Consciousness," we talked about Koch's search for the neural correlates of consciousness and the possibility that the Internet could learn to feel. Today, we conclude our conversation.

***

You like big philosophical questions, don't you?

Koch: Well, I think a lot about my place in the universe. What are we doing here? How did we come about? Does it mean anything? I like to think about these problems. You know, usually you ask these questions when you're 18 and 19, and then you get on with the business of living. Even at my age, I still ask these questions because I want to know how it all fits together before I die.

Speaking of death, you write about a night of existential angst a dozen years ago when the fact that you were going to die hit you in some very visceral way. What happened?

Koch: It was pretty late compared to most people. I felt immortal until I was 42 or so. I played one of my son's shooter video games where you are chased by hordes of aliens through empty corridors on alien suns. I did that for a couple of hours and then went to bed. Suddenly I woke up in the middle of the night with the abrupt realization that I was going to die. I didn't have any premonition that something bad was going to happen. I just knew one day I was going to die. That stayed with me for the next four to six weeks. I had a tough time until I accepted it. It's a beautiful illustration of the power of the unconscious. There I was sleeping and something was churning away, probably agitated by all that shooting and killing in the video game, and then came to some startling or unsettling conclusion, and that's when my brain decided to wake me up. Since then, unfortunately, I know I'm going to die. [Laughs.] I shouldn't have played that video game.

You write about how you grew up an observant Catholic and then lost your faith in a personal god. But it seems that the search for meaning, that yearning for the absolute, is still with you.

Koch: That's correct. I try to be guided by what's scientifically plausible. Of course, there is a huge amount of randomness, but we also find ourselves in this universe that is very conducive to life. I don't know how to explain it, but I see this arrow of progress toward an ever-larger complexity and to a larger consciousness and that fills me. I don't know what it means. I can't understand it but I see it. I observe it and I'm happy about it.

So you're not exactly an atheist.

Koch: I'm not a conventional atheist who believes it's all just a random formation. I believe there is meaning. But as you said, I don't believe in a personal god or any of the standard things that you're supposed to believe as a Christian.

Your book suggests that you're a deist, maybe believing there's some sort of supreme being that created the laws of the universe but does not intervene in it.