such a system of necessary changes in the positions of the lasting atoms. For the psychologist there is no hope of finding such necessity in the mental processes. The point is not that psychology is to-day too far removed from the fulfillment of such an ideal, the point is rather that such an ideal would be meaningless for the psychologist. His materials, the psychical contents of consciousness, are by their nature unfit to enter into such necessary connections; they cannot do it because they cannot last. The physical object, we saw, is the object which is common property, which we all feel in common, which must thus exist for all time. The things in nature may burn down or decay, but no atom of them can ever disappear from the universe, each must enter into new and ever new combinations and last through all changes. The psychical thing, on the other hand, can exist only for the one immediate experience. Every sensation which enters into my ideas or volitions or emotions is a new creation of the instant which cannot last; each one flashes up and is lost with the moment's experience. My will to-day may have the same aim as my will of yesterday, but as psychical object, my will to-day is a new will, is a new creation in every pulse beat of my life. I must will it again, I cannot store it up. And my joy of to-day can never be as psychical fact the same joy which I may have to-morrow. Mental objects as such, as psychological material, are not destined to last. It has no meaning whatever to think of their being kept over until another time. It is a coarse materialism to conceive the mental contents like pebbles which may remain on the road from one day to another. Our ideas and feelings are mental appearances which have their existence in the act of the one experience; each new experience must be an entirely new creation.