I do now see certain blackish marks on a whitish ground, and I hear certain sounds which I attribute to the ticking of my clock. In both cases I have to certain sensibles--certain blackish marks, in the one case, and certain sounds, in the other--a kind of relation with which we are all perfectly familiar, and which may be expressed, in the one case, by saying that I actually _see_ the marks, and in the other, by saying that I actually _hear_ the sounds. It seems to me quite evident that the relation to the marks which I express by saying that I _see_ them, is not different in kind from the relation to the sounds which I express by saying that I _hear_ them. "Seeing" and "hearing," when thus used as names for a relation which we may have to sensibles, are not names for different relations, but merely express the fact that, in the one case, the kind of sensible to which I have a certain kind of relation is a patch of colour, while, in the other case, the kind of sensible to which I have the same kind of relation is a sound. And similarly when I say that I feel warm or smell a smell these different verbs do not express the fact that I have a different kind of relation to the sensibles concerned, but only that I have the _same_ kind of relation to a different kind of sensible. Even when I call up a visual image of a sensible I saw yesterday, or an auditory image of a sound I heard yesterday, I have to those images exactly the same kind of relation which I have to the patches of colour I now see and which I had yesterday to those I saw then.