The appeal to the testimony of the eyes needs examination. To what eyes does one appeal? The immediately known or idea-eyes, or the "external" organs whose existence is the matter of dispute? Surely not to the last, for it is only as a result of the argument that we may assume these at all. And what hand is it so certain that I move in writing? The complex of ideas immediately known, or the something beyond, whose existence is to be established? If it be the latter, all discussion is unnecessary. If, on the other hand, the eyes and the hand concerned are ideas, it is not clear how the appeal to them can be of any service. Does a sense give anything but sensations? And if the very sense organ as immediately known be a group of sensations, how can the testimony of a sense land one in a world beyond that of sensations? And the argument that God has given me assurance of the existence of things without me, since by applying them to myself I can produce in myself pain and pleasure, presupposes that I can apply such things to myself and know that I am doing so. If this be the fact, it is trifling to discuss whether things I move to and fro exist. If, however, it is still to be proved that there are such things, and that they are moved to and fro, the argument is wholly baseless. Locke here makes appeal to the common experience that certain objects applied to the body cause pleasure, and certain others pain; a fact which no reasonable man would think of denying or questioning, as it is matter of daily observation. But in such experiences, all that is immediately evident is that an object immediately perceived (Locke's idea) is applied to another object immediately perceived (idea) with a resulting (idea) pain. Whether or not certain duplicates of the things immediately known are brought into a peculiar conjunction at the same time is wholly problematic, and would seem to remain so until some evidence be advanced of the existence of such duplicates. This argument on the part of our author shows most clearly that for the time being he lost the distinction between ideas and "real" things. They are the same in sense seventh; he assumed them to be the same in sense first. He falls into this error again and again.