What We Cannot Know: Explorations at the Edge of Knowledge

by Marcus du Sautoy

Everyone takes the limits of his own vision for the limits of the world. Arthur Schopenhauer

Everything we call real is made of things that cannot be regarded as real. Niels Bohr

If I point at something which doesn’t correspond to what society means by ‘table’, then I get corrected. Wittgenstein challenges whether the same principle can apply to naming ‘pain’. Pain does not involve an object that is external to us, or that we can point at and call pain.

‘I have a pain in my tooth’ seems to have the same quality as ‘I have a table’, and it tempts us into assuming both say the same kind of thing. You assume that there is something called ‘my pain’ in the same sense that there is ‘a table’. It seems to be saying something, but Wittgenstein believed that it isn’t really saying anything at all:

We can get at the problem of identifying what is going on inside our heads by imagining that we each have a box with something inside. We all name the thing inside ‘a beetle’, but we aren’t allowed to look in anyone else’s box, only our own. So it is quite possible that everyone has something different in the box, or that the thing inside is constantly changing, or even that there is nothing in the box. And yet we all call it ‘a beetle’. But for those with nothing in the box, the word ‘beetle’ is a name for nothing. It is not a name at all. Does this word therefore have any meaning? Are our brains like the box and consciousness the beetle? Does an fMRI scanner allow us finally to look inside someone else’s box and see if your beetle is the same as mine? Does the machine rescue consciousness from Wittgenstein’s language games?