beetle in the box

In the Philosophical Investigations §293, Wittgenstein asks us to imagine a situation in which everyone has a box into which they alone can look. Their activities can include talking about the thing, a beetle, they find in the box, but, claims Wittgenstein, the nature of what is inside the box has no place in the language. That is, it does not matter whether what each person has in their box is the same as that of others, or different, or even whether the box is empty. The nature of what is inside the box ‘cancels out’. The example and the claim are part of Wittgenstein's attack on the ‘inner theatre’ or Cartesian concept of our own privileged access to our mental states. But the analogy seems imperfectly adapted to Wittgenstein's purpose, since in the beetle case there is a sameness or difference of beetle, whether or not the people can communicate it (for this is how the case is specified), and this appears to accord well with the Cartesian theory that Wittgenstein opposed. Such theories are frequently happy with the ineffable nature of private mental occurrences. But the example comes at the end of Wittgenstein's extended treatment of the private language argument, which may be thought to have already closed off the possibility of any such theory.