1. At the beginning of what is sometimes called ‘the chapter on philosophy’ in PI, Wittgenstein remarks:

He has earlier spoken of our ‘tendency to sublimate the logic of our language’ (PI §38). It is clear that he believes that this tendency is one that he himself succumbed to in the Tractatus, and that the discussion which begins at PI §89 sets out both to characterize this tendency in detail and to point to how we might liberate ourselves from its grip.

At PI §108, he writes:

This makes clear that throwing off ‘the preconception of [the] crystalline purity [of logic]’ – which is connected with the idea of ‘sublimating’ the logic of our language – represents a decisive shift in Wittgenstein's philosophical development. The suggestion is that liberating ourselves from the grip of this idea involves ‘turning our whole inquiry round’. Insofar as he sees his own early work as governed by this idea of logic, there is an implication that Wittgenstein now believes that the direction of his investigation should be the exact opposite from the one he’d previously taken. The questions I want to consider in this chapter are: How are these ideas to be understood? What is it to ‘sublimate the logic of our language’? What is involved in ‘turning our whole inquiry round’?

2. When Wittgenstein first introduces the idea of ‘sublimating’ in the Investigations, he connects it not with his own early work but with Russell's claim that the word ‘this’ is ‘the only real name’. He describes the idea that ‘this’ is the only real name as an ‘odd conception’ which ‘springs from a tendency to sublimate the logic of our language’ (PI §38). And we can perhaps get some hint of what he thinks is involved in ‘turning our whole inquiry round’ when he responds to this ‘odd conception’ as follows: