Well,
if you ask me -- and you were wise not to --
Platonism in its place is one of the best ideas we ever had, and out of its place it's one of the worst.
As
Gorgonzola observes, it's real hard to accept the idea that there is an
ideal chairness somehow (mysteriously)
immanent in the world which is independent of the physical reality of actual chairs like them what you sits on.
William "Wild Bill" Occam throws a fit when you start dreaming up stuff like that. It doesn't explain anything that can't be explained far more sensibly in some other way, but it
was an attempt to explain something that does indeed need explaining: When you look at a chair which is different from other chairs that you've seen, you nevertheless recognize it as a chair. Not only that, but
we can conceive of "chair" independently of any particular chair.
So
what's with that?
It's
pattern recognition. The word "chair" signifies a set of characteristics, and if a thing fits the description reasonably well (
fuzzy logic blah blah blah), we call it a "chair", even if it's really a partially-hollowed-out
tree stump.
Plato saw this at work in his own mind, and he jumped to the wrong conclusion about it: He assumed that it was something external affecting his perceptions, rather than something between his ears doing the same. He described something using words, and then thought that he could learn everything there was to know about the thing merely by studying the words. He took as an
axiom the bizarre notion that language can and does provide
an accurate and complete model of reality.
Still, that's not so relevant:
Plato's been dead for years now.
What matters is the fact that we do think this way. When we say "chair", the most that that can really mean is "this is a thing that's good for approximately one person to sit on", but we've got an awful tendency to take it more seriously than that. Part of our problem is that us
monkeys on roller skates are just smart enough to screw ourselves with it: To a
dog, "
prey" == "that which darts across my field of vision", and that's that. If the cat sniffs your nose, it's a friend; if it darts across your field of vision, you eat it. No problem. The same organism is changing basic categories in the twinkling of an eye, but
dogs are
dumb as a rock and they don't care. We, on the other hand, are just smart enough to try to insist that the
cat is always one thing or the other. Well, and I'm speaking figuratively here, it ain't. See "
partisanism" for starters.
Categorizing is a good thing, though, where appropriate: When you learn to think of "
tigers" as a general class of
inimical critters, and you learn to recognize members of that class, you've got a better chance of
living long enough to breed than you would if you treated each
tiger as a unique and precious snowflake or something. Yeah, each
tiger is unique and precious in some ways, especially to its mother, but you really should face the fact that they'll all eat you. This kind of thinking can be very handy. It's why we're still around: We can generalize about things. We can assign a common identity to things that are merely similar rather than identical. It's a
blunt instrument, but a powerful one, because it provides
a very simple model of reality which is flawed only in relatively subtle ways. Call it
tempered ontological intonation, if you will: A necessary
fudge factor.
The problem (as we can learn from anybody who's ever driven through
New Jersey with a dark
complexion) is that
blunt instruments are just that:
Blunt instruments. They're worse than useless when it comes time to slice a
tomato, and in this world of ours there are
tomatoes a-plenty to be sliced.
Blunt instruments like "
horse" and "
tiger" are great when you need a fast way to escape something that might want to eat you, but when it comes time to study
taxonomy (for example), they're maddeningly clumsy. Throw in
evolution (for a better example) and you're in serious trouble: At one point there was
eohippus, and now there is
horse. At what point did the change happen? To which individual do you point when you say, "this is
horse, and its parents were
eohippus"? None, none at all. It's ridiculous on the face of it.
There is no place to draw that sharp dividing line which
taxonomy and
Plato both demand that we draw between one word (and/or that which is signified by that word;
same difference in their terms) and the next. You can pretend to draw the line only if you take widely separated samples and refuse to think about all the fine gradations which necessarily lie between them.
If there are any
creationists in
the studio audience tonight who have a fondness for
Borges, they could do worse than to refute
evolution on
ontological grounds: It is an
axiom that an animal must be wholly a member of one category or another. An "
intermediate form" is inconceivable
and therefore unreal. I guarantee you, you'll find people who find that convincing. The trick is to move from the indefensible
axiom to the
logic quickly enough to get 'em worrying about the
logic instead. That way, they'll implicitly accept the really destructive part and concentrate on
biting the feathers. Once they've done that, they're sunk.
Computer programming, by the way, is fun and fascinating precisely because a
computer is a funny little man-made world where
Platonism does provide
an accurate and complete model of reality.