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Saturday, March 22, 2014

Cratylus and Kripke

I've just turned my attention to Plato's Cratylus for the first time.  Nothing of significance brought it to my attention, but when I learned it is considered his only sustained treatment of language, and that it deals with the question of whether meaning is natural or conventional, I thought I should become familiar with it.  I have only looked at the very beginning, but already I wish I had more time to explore it and its relation to 20th-century philosophy of language.

At the beginning of the dialogue, Hermogenes affirms a view of names which is relativistic:  the designation of a name is entirely dependent on conventional usage.  The rightness or wrongness of word meaning is relative to a linguistic community.  If I use the word "horse" to refer to humans, and "human" to refer to horses, then I am right as far as my own usage goes, though I am not in line with the majority.

Socrates leads Hermogenes to find a problem with this view with a curious argument.  He gets Hermogenes to admit three points:

(1) Propositions are either true or false.
(2) The most basic element of a proposition is a name.
(3)  If a proposition is true or false, then its parts are true or false.

From this it follows that names are either true or false.  So there must be something wrong with Hermogenes' conventionalism.

It would seem that (3) is a point of weakness in Socrates' argument, but I want to suggest otherwise.  We might be tempted to say that only propositions as a whole can be true or false.  In one sense, this is correct.  Propositions predicate properties, and in this way they can be true or false in ways which names cannot.  That is, unless we take names to also predicate properties to their designators--however, if we did that, then we would arrive at an infinite regress, because every name would express a proposition which would be composed of yet more names, ad infinitum.  So there must be a sense in which propositions do more than individual names; and there is a sense in which they alone, only as a whole, can be true or false by virtue of that function.

I'm afraid it is too easy to use this point to reject Socrates' argument.  I have not read further into the dialogue than this, so I am not sure what Plato makes of it.  But just taking the argument as it stands, I think we can find something much more interesting to consider about it.  For there is another sense in which a proposition can be true or false:  namely, a proposition can be true or false in so far as it is used correctly.  This is what Kripke calls truth in a metalinguistic sense (see Kripke's Wittgenstein on Rules and Private Language).  If we abandon the notion of metalinguistic truth, Kripke suggests, we undermine our very conception of meaning.  (Actually, this is not necessarily Kripke's argument; it is an argument Kripke formulates as inspired by Wittgenstein, and so it may be better to call it "Kripkenstein's argument.")

In short, Socrates' argument may be this:  If we adopt conventionalism with respect to names, we are claiming that metalinguistic truth is relative, and so the objective truth of all of our utterances is undermined.

I don't know when I'll have time to read the rest of Plato's dialogue or to investigate the literature on it.  I haven't even read as much Kripke as I should.  For now I can only appreciate the intriguing connection between Plato's thought and 20th-century philosophy of language.