cognitive farmers

[From Bill Powers (930909.1100 MDT)]

Oded Maler (930909.1730) --

Some fine words lately, Oded.

There is a real farmer with real bird, real fox etc. When he
has to solve his *real* problem, he has to perceive the bird,
the river, the boat, etc., counteract disturbances, digest and
breath meanwhile, and a lot of other things.

Cognitive science/symbolic AI approach says: a prerequisite for
an agent to solve the *real* version of the problem is to solve
the abstracted symbolic problem. If we cannot design an
architecture to solve puzzles (where we provide the
abstractions), we have no hope to build systems that in
addition have to do the abstraction themselves. That's way we
should investigate symbolic architectures.

Right, that seems to be the rationale. But there is an added
assumption, which is that the problem is going to be solved in a
particular computer-like way. The real farmer may think, "Gee, I
can see the puzzle: I can't leave the chicken with the grain or
the fox with the chicken -- looks impossible, I give up." Then,
having given up solving that problem, he may simplify the
problem: "Basically, do I really care if the chicken eats a
little of the grain? I guess not." Or he bops the fox over the
head with an oar so he can leave it with the chicken while he
goes back for the grain. Or he wrings the chicken's neck so he
can leave it with the grain while he goes back for the fox --
after all, we're having the chicken for dinner tonight anyway.

When I think of the chicken-fox-grain problem and play by the
rules, I don't solve it by logic: I do it in imagination. I try
taking the grain across, and realize that oops, the fox is eating
the chicken, I can't do that. I try taking the chicken across,
but then realize on the next trip that I'll be leaving the grain
for the chicken to eat or the fox to eat the chicken. In other
words, I just zip through the possibilities in imagination and
experience what's wrong with them. Then, for a moment, I'm
stumped. The solution comes out of the blue: Ah, of course, I can
bring the chicken back with me when I take the fox over. Then I
can see why I didn't get the solution right away: the way the
problem is stated, it refers only to transporting items in one
direction. So I failed to include the premise that I could
transport things either way. If I'd thought of that first, the
solution would have been trivial: just do things in the right
sequence and nobody eats anything forbidden. The solution isn't
in finding the right logic, but in finding the right sequence,
which I can do without logic.

Computers can't perceive sequence without a lot of elaborate
programming. I can. Give me A, B and then B, A, and I can tell
you immediately that the sequences are different. The computer
has to be programmed to go through an elaborate series of logical
tests involving whether A is in memory while B is being sensed
and vice versa, and then comparing the results for the two cases,
which gets the job done but slowly. I have hardware for detecting
sequence immediately.

If you give me a real logical problem, which involves the
simultaneous truth-values of several propositions, I have to
dredge up my Boolean algebra and work it out the same way the
computer has to work it out, if it's programmed to do Boolean
algebra. I would do it a lot slower, because I have to remember
the rules and apply them, and probably write them down so I don't
forget where I am. The Boolean algebra I'm using doesn't explain
what I'm doing, of course, which is following rules, a non-
Boolean process. What really needs explaining is not the logic,
but how I can follow rules, as I said a little earlier today.
That would be a basic cognitive function.



Bill P.