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Alan Alda in Scientific American Frontiers
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photo of Alan and DennettRenowned philosopher Dr. Daniel C. Dennett enjoys getting to the bottom of some of life's biggest questions; where did we come from, and what makes us human? His search for the answers has led him down some unexpected paths. The author of several books, including "Consciousness Explained" and "Darwin's Dangerous Idea," Dennett sat down recently with Alan Alda.
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Uniting Philosophy & Science

ALDA: I've always thought that there was a kind of a growing apart of philosophy and science.

DENNETT: I think that the idea that philosophy and science are so distinct is a fairly recent idea in the last 150 years or so. If you go back a few hundred years you see that Kant and Hume and Descartes either were scientists or were intimately involved in thinking through the scientific problems of the day. I think that we're returning to that now and it's a very good thing.

ALDA: Did your interest in Darwin develop once you started to get more intimately involved in science, or did you start out interested in Darwin?

DENNETT: The first problem that really grabbed me was the question of how on Earth a brain can learn. I thought there's got to be some way that neurons can try things out by trial and error and in effect get punished for getting it wrong and encouraged for getting it right. The more I looked at evolution, the more it seemed that this was the central idea that could explain all processes of design improvement. That's what learning is. You're redesigning yourself a little bit better.

Know Thyself

We know what we are. Dogs don't know they're dogs


DENNETT: We're the only species on the planet that knows what they are. We've only known it for a century or so- because we developed science. And we developed science after we'd first developed religion and government and reading and writing. We know what we are. Dogs don't know they're dogs.

ALDA: How do we know that dogs don't know that?

DENNETT: Dogs know who their rivals are, they know what to mate with, roughly speaking.

ALDA: Sometimes they don't seem to when they go after your leg.

DENNETT: That's right. And that's actually a sort of good measure of how crude their discrimination capacities are. They have a few simple rules and they're just born knowing those rules. They don't really understand them.

ALDA: And yet how do we know that?

DENNETT: And how do we know the chair you're sitting in isn't thinking, "well, gee, I'm just a chair." At some point, we say, this is just a silly hypothesis.

ALDA: You have a preprosterosity gauge.

DENNETT: Exactly. There are some hypotheses that are just too ridiculous to take seriously. Now we sometimes make mistakes about which those are but I think the hypothesis that the chair is thrilled to be holding you up right now is one that we can eliminate. The chair, it's clueless. And the bacteria are clueless. And the oak trees are clueless. That doesn't mean that (higher animals) can't be hurt, that they can't enjoy, but it's a much more sort of one-dimensional sort of thing, whereas ours is multidimensional.

ALDA: How do you suppose we got that way? Was there some turning point in the history of life on this planet or in the history of human life that was crucial?

DENNETT: I think that one of the keys to understanding this joint between the purely mindless mechanical world and the mind is to recognize that the transition is gradual. These are just simple switches and springs and so forth. And yet, when it gets organized, it gets organized by an algorithmic process, by natural selection. It takes on just the tiniest bit of mentality. It does something that we think of as requiring a mind. That's what I call the intentional stance. Think of something as simple as a mousetrap. It's set up, it's open, it's waiting. Well, there's one little thing it can do. It can snap. And it may snap at the right sort of thing, it may snap at the wrong sort of thing.

ALDA: That's vastly different nevertheless, from a chair, isn't it, because the chair doesn't do anything.

DENNETT: Right there. The difference between a mousetrap and a chair is the sort of tiny little difference that you want to build the big differences out of. That's Darwin's message.

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