§58

I'm not sure what Wittgenstein is saying here. He suggests that we might want to say that 'red exists' does not make sense. Is the reason for this that propositions that make sense must be bipolar and 'red exists' is not bipolar (because 'red', as a simple object, must exist)? - This sounds as though Wittgenstein is attacking the 'metaphysical' claims of the Tractatus.

(Here's Hacker's summary of the argument of Wittgenstein's interlocutor in §58: "The argument is that one cannot say 'red exists', since one cannot assert its negation 'red does not exist', because if red didn't exist, one could not speak of it in order to say that it does not exist.)

Wittgenstein suggests that this isn't far from being correct but in fact the reason we're tempted to say this is that red things play the role of samples - and so belong to language (am I getting him right here?).

All we're saying when we say that 'red exists' is that there are things with that colour.