Of the communicability of a Sensation

If sensation, as the real in perception, is related to knowledge, it is called sensation of the senses; and its specific quality may be represented as generally communicable in a uniform way, if we assume that everyone has senses like our own. But this cannot at all be presupposed of any single sensation.

To a man who is deficient in the sense of smell, this kind of sensation cannot be communicated; and even if it is not wholly deficient, we cannot be certain that he gets exactly the same sensation from a flower that we have. But even more must we represent men as differing in respect of the pleasantness or unpleasantness involved in the sensation from the same object of sense; and it is absolutely not to be required that every