Is consciousness something distinct from the intellectual operations named perceiving, conceiving, reasoning, recollecting, imagining; or do these operations ever take place in the absence of consciousness? In order to answer this vital question it is necessary that consciousness should be examined with a microscopic nicety, rarely, as we take it, attained to since Reid explored this field of science. When we consider that, for forty years, Reid, with an enthusiastic admiration for that inductive method which the genius of Newton and others illuminated with such brilliancy, questioned Nature, Nature in man, as to the character of perception, and decided that the objects disclosed by it were not mentally possessed; investigators are bound, for their own credit's sake, to show beyond doubt that Reid is in error before they flippantly accuse him of being singularly wanting in penetration. Yet the conclusion which is forced upon us by the present aspect of psychology and cerebral physiology, not to mention metaphysic, is to the effect either that Reid was singularly wanting in analytical ability, or that the living race of psychologists must be going far astray on a most vital point. We have lately been forced to believe that Reid is on the right road; yet, sooth to say, during many years objects have been to us, as it would seem to psychologists in general, a most fertile source of perplexity and confusion. It is only very lately we have succeeded in realising the fact that the object, or the known, is not an element of the knowing; that knowing is not knowing plus known, but knowing purely and simply, a single fact, not a double one; not a synthesis of consciousness and object, but consciousness only, that and nothing more.