Wittgenstein Asked Each of Us to Imagine a Beetle in a Box

Ludwig Wittgenstein left Cambridge in 1947 and spent his last years drafting the manuscript that became Philosophical Investigations, published in 1953, two years after his death. The book moves by short numbered remarks. Section 293 introduces what is now usually called the beetle-in-a-box.

Suppose, he writes, that everyone had a box with something in it that we call 'a beetle.' No one can look into anyone else's box. Each of us only knows what a beetle is from looking at our own. It might be that everyone has something different. It might even be that the thing in the box keeps changing, or that the box is empty.

Now consider what happens when we use the word 'beetle.' The word is part of a public language. We learn it from each other, correct each other's use, agree and disagree about its application. But the private object in the box plays no role in any of that. Whatever is in there 'cancels out, whatever it is.' The grammar of the word is fixed by what we do with it together, not by what each of us inspects in private.

The target is what philosophers call private-language theories of meaning, in particular the picture of sensation words like 'pain' as labels each speaker pins onto a private inner item. If pain were such a label, Wittgenstein argued, we would be in the beetle case: each of us with a private referent, none of which actually bears the meaning of the public word.

The argument has been picked over for seventy years. It does not show that there are no inner experiences. It shows that whatever is in the box, the public word does not get its meaning from it.