THE PHYSICAL CONDITIONS OF CONSCIOUSNESS. 491

there is no consciousness apart from the particular act or state of consciousness. Indeed, it may be questioned whether it is right to speak of ' states of consciousness ' ; it would be more correct to speak of states of mind, or of functions of mental organisation, which may be conscious or not. Again, consciousness is not, as commonly implied, of constant quality or quantity, but is actually as follows necessarily also from what has just been said an extremely inconstant and variable state ; varying in degree from the greatest intensity down to zero, and in quantity from a large expanse down to a vanishing point. Being incident to the particular mental state, and to the particular tract of nervous substratum subserving that state, it is qualified and localised thereby. Anyone who will attend closely and patiently enough to his own consciousness, when thinking, may dis- cover, perhaps, that he never does think with his whole brain, and suspect even that he thinks with different strands of it when thinking of greatly different interests and situations. If it be not right to speak of consciousness as having extension and being divisible into parts, that is for the same reason that it is not right to speak of one sense in the terms of another to speak of a loud smell, a red taste, a shrill touch, a bitter sound. The cogito ergo sum of Descartes, if translated fully by ex- position of its implications, would run thus : I (who am) think, therefore I (who think) am. The axiom implies tacitly, whether designedly or not, that consciousness is not the fundamental fact of being, although, no doubt, my con- sciousness is the fundamental fact of my conscious being. Everybody who wishes to be understood seriously takes it for granted that he exists, even when he is not conscious, in a scheme of things which exists when he is not conscious of it. There is the conscious /, and there is the unconscious /. Now the conscious /, when I reflect, certainly does not include the whole 1 ; the / who reflect is not ever inclusive of the whole contents of my personality : it is the I of the moment that is, of the then mode of my Ego ; which may be very different from the Ego of twenty-four hours before or afterwards, and is certainly different, never exactly the same, on every occasion of my thinking. If the subject of which I think interest me not deeply, the reflection on it is a reflec- tion on it by a part of me ; if it interest me more deeply, the reflection on it engages more of my mental being ; if the situation be congenial and grateful, the reflection on it is by one part of my mental being predominantly ; if it be dis- agreeable and uncongenial, it is by another part of my