is a point that can only be determined by experience; and what says that wise instructor? We withdraw the tangible object. The visible object, too, disappears: it leaves its place. We replace the tangible object—the visible object reappears in statu quo. There is no occasion to vary the experiment. If we find that the visible object invariably leaves its place when the tangible object leaves its, and that the one invariably comes back when the other returns, we have brought forward quite enough to establish an inevitable association in place between the two. The two places are henceforth regarded not as two, but as one and the same.
By the aid of the touch, then, we have associated the visual phenomena with things which are not the organ of vision; and well it is for us that we have done so betimes, and before we were aware of the eye's existence. Had the eye been indicated to us in the mere act of seeing, had we become apprised of its existence before we had associated our visual sensations with the tangible objects constituting the material universe, the probability, nay the certainty, is that we would have associated them with this eye, and that then it would have been as impossible for us to break up the association between colours and the organ, as it now is for us to dissolve the union between colours and material things. In which case we should have remained blind, or as bad as blind; brightness would have been in the eye when it ought to have been in the sun; greenness would
