The effort is accompanied by a muscular sensation, and the sensations themselves are connected with certain physical conditions which probably count for something in the estimate of their intensity: we have here to do with phenomena which take place on the surface of consciousness, and which are always connected, as we shall see further on, with the perception of a movement or of an external object. But certain states of the soul seem to us, rightly or wrongly, to be self-sufficient, such as deep joy or sorrow, a reflective passion or an aesthetic emotion. Pure intensity ought to be more easily definable in these simple cases, where no extensive element seems to be involved. We shall see, in fact, that it is reducible here to a certain quality or shade which spreads over a more or less considerable mass of psychic states, or, if the expression be preferred, to the larger or smaller number of simple states which make up the fundamental emotion. [Sidenote: Take, for example, the progress of a desire.] For example, an obscure desire gradually becomes a deep passion. Now, you will see that thee feeble intensity of this desire consisted at first in its appearing to be isolated and, as it were, foreign to the remainder of your inner life. But little by little it permeates a larger number of psychic elements, tingeing them, so to speak, with its own colour: and lo! your outlook on the whole of your surroundings seems now to have changed radically. How do you become aware of a deep passion, once it has taken hold of you, if not by perceiving that the same objects no longer impress you in the same manner? All your sensations and all your ideas seem to brighten up: it is like childhood back again. We experience something of the kind in certain dreams, in which we do not imagine anything out of the ordinary, and yet through which there resounds an indescribable note of originality. The fact is that, the further we penetrate into the depths of consciousness, the less right we have to treat psychic phenomena as things which are set side by side. When it is said that an object occupies a large space in the soul or even that it fills it entirely, we ought to understand by this simply that its image has altered the shade of a thousand perceptions or memories, and that in this sense it pervades them, although it does not itself come into view. But this wholly dynamic way of looking at things is repugnant to the reflective consciousness, because the latter delights in clean cut distinctions, which are easily expressed in words, and in things with well-defined outlines, like those which are perceived in space. It will assume then that, everything else remaining identical, such and such a desire has gone up a scale of magnitudes, as though it were permissible still to speak of magnitude where there is neither multiplicity nor space! But just as consciousness (as will be shown later on) concentrates on a given point