things are represented by little images in the mind. Unquestionably, that view is a gross exaggeration of the real opinion. All that philosophers meant was, that we had perceptions of objects, and that these perceptions were not the objects themselves. Yet even this, the least exceptionable form of the theory that can be maintained) was found sufficient to subvert the foundations of all human certainty.
Here, then, it was that doubts and difficulties began to break in upon philosophical inquiry. It was at this juncture that the schism between common sense and philosophy, which has not yet terminated, began. People had hitherto believed that they possessed an immediate or intuitive knowledge of an external universe; but now philosophers assured them that no such immediate knowledge was possible. All that man could immediately know was either the object itself, or his perception of it. It could not be both of these in one, for this explanation of perception was founded on the admitted assumption that these two were distinct, and were to be kept distinct. Now, it could not be the object itself, for man knows the object only by knowing that he perceives it—in other words, by knowing his own perception of it; and the object and his perception being different, he could know the former only through his knowledge of the latter. Hence, knowing it through this vicarious phenomenon, namely, his own perception of it, he could only know it mediately; and therefore it was merely his own perceptions of an external uni-
