What are mental images? Traditionally, philosophers have taken them to be representations of a certain kind. In common with all representations, they are seen as the kinds of thing that can be coloured, noisy, odorous, palpable or tasty, depending upon what they are representations of. But, in The Concept of Mind, Professor Ryle argues that this view of mental imagery is incoherent. Anything, he says, that really is coloured or noisy and so on, must, in principle, be locatable, which mental images are not. He concludes that they cannot be the kinds of thing that the traditional view asserts them to be. Indeed, he goes further: he maintains that everything that exists has at least one of the properties mentioned in the above list and that, since mental images fail in this regard, they do not exist.
Unfortunately, Professor Ryle's arguments in support of his contention that mental images are unlocatable are not conclusive. He assumes that if one can show that mental images are not locatable in ordinary space, they are not locatable in principle.