  The notion ‘type’ and ‘token’ here comes by analogy from ‘type’ and ‘token’ as applied to words. A telegram ‘love and love and love’ contains only two type words but in another sense, as the telegraph clerk would insist, it contains five words (‘token words’). Similarly a particular pain (more exactly a having a pain) according to the token identity theory is identical to a particular brain process. A functionalist could agree to this. Functionalism came to be seen as an improvement on the identity theory, and as inconsistent with it, because of the correct assertion that a functional state can be realised by quite different brain states: thus a functional state might be realised by a silicon based brain as well as by a carbon based brain, and leaving robotics or science fiction aside, my feeling of toothache could be realised by a different neural process from what realises your toothache. 