Monday, November 12, 2007

5.5303 Roughly speaking: To say of two things that they are identical is a nonsense [Unsinn], and to say of one thing that it is identical with itself is to say nothing at all [gar nichts].

What’s the difference? Between speaking nonsense and saying nothing, and between saying “two objects have all their properties in common” and saying “two things are identical”? And why “roughly speaking” [beiläufig gesprochen] here?


Ponder Stibbons said...

My interpretation is probably rather crude but here goes:

Two objects might have all properties in common without being the same object. Whereas I think he takes "two things are identical" to mean "these two things are really the same object". This has to do with the identity of indiscernibles --- someone who believes in II would see no difference between the two statements.

Saying nothing is saying something that is, I suppose, trivially true. Speaking nonsense is (roughly!) attributing a property/state to things that they could not possibly have. So two things could not be identical because if they were, they could not be referred to as two things. We can speak in the plural only for different things.

DR said...

Well, that seems reasonable (not too crude). There is a kind of contradiction in saying "These two things are not two but one," although it isn't too hard to imagine those words being said meaningfully (perhaps with scare quotes around the word "two"). For instance, if an illusion using mirrors made it appear that there were two things when really only one was present. Given the contradiction, it seems reasonable to talk of nonsense here.

But is saying of one thing that it is identical with itself trivially true? Perhaps it depends how we define "identity with self."

The puzzle here, such as it is, stems from the facts that I wouldn't have expected Wittgenstein to make a distinction between talking nonsense and saying nothing at all, and that I would have expected him to count talk of self-identity as nonsensical. So perhaps I should just change my expectations.