Wittgenstein on why anything exists

The Maverick has picked up my post on Siger, which itself picks up an earlier post of his.  Is Siger's approach 'rejectionism'? "The rejectionist rejects the question as ill-formed, as senseless."  Or is it 'Theologism'? "There is a metaphysically necessary and thus self-explanatory being, God, whose existence and activity explains the existence of everything other than God."

Bill mentions my remark about Wittgenstein, but I can't locate the paper I was thinking of. It was after the Tractatus and either shortly before or shortly after he returned to Cambridge, and it began with the question of why anything exists at all.  I can clearly remember looking at it (in Bristol in the early 1980s), but can't locate it.

Meanwhile, I did find an interesting snippet which I quote at second hand from Anthony Kenny's book Wittgenstein.  My emphasis:

Logic depends on there being something in existence and there being facts; it is independent of what the facts are, of things being thus and so. That there are facts is not something which can be expressed in a proposition. If one wants to call there being facts a matter of experience, then one can say logic is empirical. But when we say something is empirical we mean that it can be imagined otherwise; in this sense every proposition with sense is a contingent proposition. And in this sense the existence of the world is not an empirical fact, because we cannot think it otherwise (WWK* 77).

Bear in mind that this is Kenny paraphrasing Wittgenstein. But it looks like a genuine form of 'rejectionism' to me.  Is it true?

*Ludwig Wittgenstein und der Wiener Kreis, shorthand notes of F. Waismann, ed. McGuinness, Basil Blackwell, 1967.