As
Lenin famously pronounced in this pseudo-philosophical statement, “matter is
objective reality which is given to us in perception.” Our friend Bertrand
Russell, too, reasonably starts his analysis of Plato’s theory of knowledge and
perception, with the reminder that normal people have usually taken it for
granted that all knowledge comes to us through the experience of our senses,
that is perception. Curiously enough the same premise opens Plato’s Dialogue Theaetetus,
but not to reiterate what could easily be mistaken for a truism, but rather to
set up a punching bag, which the rest of the Dialogue proceeds to cut up to
shreds. Here is that opening setup:
Socrates: Once
more, Theaetetus, what is knowledge? and do not say that you cannot
tell; but quit yourself like a man, and by the help of God you will be able to
tell.
Theaetetus:
After this, Socrates, I should be ashamed not to try my best. He who knows, perceives
what he knows, and, as far as I can see, knowledge is perception.
To
which Socrates reacts:
Socrates:
Well, you have delivered yourself of a very important doctrine about knowledge;
it is indeed the opinion of Protagoras, who has another way of expressing it. Man,
he says, is the measure of all things, of the existence of things that are,
and of the non-existence of things that are not… Then, doesn’t he say that
things are to you such as they appear to you, and to me such as they appear to
me? Then, perception always is of existence, and being the same as knowledge is
unerring?
Anybody
who is familiar with Plato’s Socrates realizes at this point that what Socrates
is driving at, is that perception cannot be knowledge. Through a rather lengthy
series of arguments, Plato’s Socrates is, indeed, coming to his final point
concerning the inadequacy of perception as knowledge. We perceive through our
eyes and ears and not with them. Some of our knowledge is not connected
with any sense organ at all. The mind contemplates
some things through its own instrumentality, others through the bodily
faculties. Only the mind can reach existence,
and we can’t reach truth, if we don’t reach existence. It follows that we can’t
know things through the senses alone, since through the senses alone we can’t
know that things exist. Ergo, knowledge consists in reflection, and not in
impressions, and perception is not knowledge because “it has no part in apprehending truth, since it has none
in apprehending existence.” (The teal font
here belongs to Russell quotes.)
Now,
rather than going into the details of the Theaetetus, I recommend to the
reader to read this Dialogue if these details are of interest to him, or her.
On my part I would like to add a few comments on Plato’s use of mathematics and
linguistics in this context. Here again is Bertrand Russell, whose thoughts on
Plato’s math I am quoting here to establish a point of reference for further
exploration at a later date.
I come now to understanding of numbers. There are two very
different things to consider here: on the one hand, the propositions of
arithmetic (2+2=4), and, on the other, empirical propositions of enumeration (“I
have ten fingers”).
I should agree with Plato that arithmetic, and pure mathematics
generally, is not derived from perception. Pure mathematics consists of
tautologies, analogous to “men are men,” but usually more complicated.
To know that a mathematical proposition is correct, we do not have to study the
world, but only the meanings of the symbols; and the symbols are found to be
such words as “or” and “not” and “all” and “some,”
which do not, like “Socrates,” denote anything in the actual world.
Mathematical truth is, indeed, independent of perception; but it is truth of a
very peculiar sort, and is concerned only with symbols.
Propositions of enumerations are in a different category, and are,
at least in part, dependent on perception. Thus, in the statement “I have
ten fingers” perception clearly plays a smaller part, and conception, a
larger part, than in the statement “this is red.” The matter, however,
is only one of degree.
These considerations show that, while there is a formal kind of
knowledge, such as logic and mathematics, which is not derived from perception,
Plato’s arguments regarding all other knowledge are fallacious.
And
finally, in his involvement of linguistics, which is particularly familiar to
me, as a professional, in all its aspects, Plato apparently gets lost in the
intricacies of the science of language sorely undeveloped in his day and even
much later. In the following classic passage, known as the Socrates Dream, an
atomistic generalization of language is promoted, comparing letters to elementary
particles [atoms], and their complex combinations to [molecules]. (This is obviously
my shorthand word here. Socrates never uses it). After this discussion, it
should become clear why the philosophical discourse in the Theaetetus will
remain admittedly inconclusive.
Socrates: I
too had a dream, and heard in my dream that the primeval letters, or elements,
out of which you and I and all other things are compounded, have no reason or
explanation: you can only name them, but no predicate can be either affirmed or
denied of them, for in the one case existence, in the other non-existence is
already implied, neither of which must be added, if you speak of this or that
thing by itself. It should not be called itself, or that, or each, or alone, or
this, or the like, for these go about everywhere, and are applied to all
things, but are distinct from them; but if the first elements could be
described, and had a definition of their own, they would be spoken of apart
from all else. But none of these primeval elements can be defined, but they can
only be named, for they have nothing but a name, and the things compounded of
them, as they are complex, are expressed by a combination of names, for the
combination of names is the essence of any definition. Thus, the elements or
letters are only objects of perception and cannot be defined or known; but the
syllables or combinations of them are known, and expressed, and apprehended by
true opinion. When, thus, anyone forms the true opinion of anything without a
rational explanation, you can say that his mind is exercised, but has no
knowledge, for he who cannot give and receive a reason for a thing has no
knowledge of that thing; but when he adds rational explanation, then he is
perfected in knowledge.
In
semantics, Plato’s confusion arises from a lack of proper understanding of how
words acquire their original meanings, and how these meanings never remain
fixed, but undergo gradual changes, which, however, are not to be ignored or
exaggerated, and even less ridiculed. To be sure, the formal language of
mathematics answers to different laws than any living language, and attempts to
create artificial languages designed for international communication have
famously failed. My general understanding of Plato’s linguistic failure is that
he wished to treat the living language just like certain linguistic engineers
more than two millennia later wished to see the artificial product of their
engineering, but unlike Plato, they understood that none of the existing
languages was fit for that function.
…Just
as I was about to say au revoir to the Plato subsection, the idea for an
offshoot for this last entry has come to me, with the natural title Plato’s
Problem, referring to the gap between knowledge and experience, described
and so named by none other than our friend Noam Chomsky. And so, welcome now to
what has received the name Plato’s Problem, courtesy of Ecce Chomsky.
(My very long entry devoted to Chomsky and boasting of this fancy title Ecce Chomsky will be posted (necessarily,
in terms of chronological continuity) much later,
after I am done with all earlier giants
of Western philosophical thought.)
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