The Table Video

Is your mind just a biological computer? Mark Baker (Rutgers University) comments on the differences between the human mind and computers.

Transcript:

Cognitive scientists have sometimes suggested that the human mind is like a very complicated computer, and we can explain everything that goes on in a computer by appeal to its physical parts and their functions. We’ve been talking about one dimension of the human mind that seems importantly different from computers, its capacity for free choice, and the way that shows up in language use. Are there other dimensions of the human mind that you think are importantly different from computers?

Well maybe, it is generally true that a computer will only do what it’s programmed to do. And what a computer does is deterministic function of what’s put into it, and we don’t have any evidence that that’s true for us. That doesn’t mean computers don’t surprise people because they’re so complicated there might have been a mistake in them or something, where they’ll do something surprising to the programmer, but that’s an accident when that happens.

Another thing that I’d been thinking about recently is one of the special properties that our thoughts apparently have is that they can be true or false. So I can say to you, “It’s raining, today” and that has a certain meaning, it means that it’s raining today. And either that’s true or false, and that fact we can look that up. But natural systems don’t typically have that property. Any kind of, you know if you have a certain rock or something it might show the effects of things that have happened to that rock in some way or another.

It might show that somebody hit it with a pickax, but that rock doesn’t say, “I was hit by a pickax” and it’s not saying, “True, John hit me with a pickax” and, “False, Mary hit me with a pickax.” And that’s probably true even of computers that they have, they might represent various things. But they don’t in and of themselves have the property of being true or false of those things.

Can we explore that a little further, so you might have thought that, insofar as something is capable of encoding information, if it can have information in it, a rock face can contain information about its causal history, or we talk of storing information in our computers and you might have thought, insofar as something can encode information, it can thereby be either true or false, the information thus encoded can be true or false. You’ve argued not so, there’s an important difference between the encoding, some things being able to encode information, and some things being true and false. Why think that?

Well this is something that’s just occurred to me pretty recently and how important that distinction might be. But so suppose a geologist is studying a cliff face in the Grand Canyon say, and sees there’s maybe 13 layers of rock on that cliff face and he deduces rightly or wrongly there were 13 different geological ages, that come from that.

So did the cliff face have information about when that part of the world was underwater or whatever, or not? Yes, absolutely, there is information there about what happened to make all those rocks. But is that cliff face true or false about that? So imagine one of the layers of rock is missing there. Is that layer, is that cliff face false because it says there were 12 geological ages when really there were 13? Well, I would say no, it’s misleading, but it’s not false. There was some other factor that went into making that, that you didn’t know and you got confused.

So my idea, studying that might be false, but the cliff face itself isn’t false. So natural objects like cliff faces, they can give all kinds of information of the things that have caused them or affected them, but they’re not specifically true or false the way our human ideas or our human language are true or false.

And sentences on a page are, on one way of thinking about it, natural objects just as are rock faces and yet clearly you do think that sentences on a page can be true or false. What’s the added kick that they get, that the rock face doesn’t have such that they can be true or false?

Well I think the added kick is that they were written by someone with a mind, with an intention to communicate a certain thought. You could actually say that even the sentences on the page are not really true or false, ’cause most sentences have some degree of ambiguity or something in them. So you need to say, okay well what was intended.

If I say this was big, do I mean this is big compared to small things or do I mean this is big compared to other things? You don’t actually know whether that’s true or false until all the ambiguities have been resolved. So it’s really not the sentence that’s true or false, it’s the thought that was expressed by the sentence, that was true or false. So I think you could still say that only thoughts are true or false, since there’s something very special about those.