Aristotle Metaphysics
Part 2
Realism
You might think that Plato has gone
off the rail a bit; Aristotle certainly thought so.
Although something
like Plato’s theory is very hard to avoid.
Over and above this or that particular
triangle, we have the universal “triangularity”; over and above this or that
particular human being, we have the universal “humanness”; over and above this
or that particular red thing, we have the universal “redness”; in general, each
particular thing seems to instantiate or exemplify various universal features.
The particular things are unique and non-repeatable, but the features they
exemplify (e.g. “humanness”) are repeatable and common to many things, hence
“universal’.
Numbers are not physical objects: the
numeral “2” isn’t the number 2 any
more than the name “George” is the same thing as the man George.
They are
necessary truths rather than contingent ones.
To know
that 2+2=4 is to know a necessary
truth, one that could not have been
otherwise. It would remain true even if the entire universe collapsed in on
itself.
Statements about the world, whether
true or false, which are distinct from the sentences that express them. “John
is a bachelor” and “John is an unmarried man” are different sentences, but they
express the same proposition. When Socrates and Ben Gallant think that snow is
white, they are thinking exactly the same
thing, despite the fact that one of them expresses this thought in Greek in
the Athens of the 5th century B.C., and the other in English in 21st
century Canada.
Being
different from any sentence, or indeed from any other sequence of physical
sounds or shapes we might use to express them, propositions are in some sense
distinct from the material world. But since a proposition is either true or
false whether or not we happen to be entertaining it—again, 2+2=4 would be
still be true even if we forgot this tomorrow, 2+2=5 would be false even if we
all came to believe it, and snow was white long before anyone first saw it—it
seems to follow that propositions are also independent of any mind.
The
view that universals, numbers, and/or propositions exist objectively,
apart from the human mind and distinct from any material or physical features
of the world, is called realism.
It can seem
at first glance to be very dry, esoteric, and irrelevant to practical life. But
nothing could be further from the truth, as we shall see.