THE "PHYSICALLY BEAUTIFUL" IN NATURE AND IN ART [Sidenote: _Æsthetic activity and physical concepts._] Æsthetic activity, distinct from the practical activity, is always accompanied by it in its manifestations. Hence its utilitarian or hedonistic side, and the pleasure and pain which are, as it were, the practical echo of æsthetic value and disvalue, of the beautiful and of the ugly. But this practical side of the æsthetic activity has in its turn a _physical_ or _psycho-physical_ accompaniment, which consists of sounds, tones, movements, combinations of lines and colours, and so on. Does it _really_ possess this side, or does it only seem to possess it, through the construction which we put on it in physical science, and the useful and arbitrary methods which we have already several times set in relief as proper to the empirical and abstract sciences? Our reply cannot be doubtful, that is, it must affirm to the second of the two hypotheses. However, it will be better to leave this point in suspense, since it is not at present necessary to press this line of inquiry further. The mere mention suffices to secure our speaking (for reasons of simplicity and adhesion to ordinary language) of the physical element as something objective and existing, against leading to hasty conclusions as to the concepts of spirit and nature and their relation. [Sidenote: _Expression in the æsthetic sense, and expression in the naturalistic sense._] It is important, on the other hand, to make clear that as the existence of the hedonistic side in every spiritual activity has given rise to the confusion between the æsthetic activity and the useful or pleasurable, so the existence of, or rather the possibility of constructing, this physical side, has caused the confusion between _æsthetic_ expression and expression _in a naturalistic sense_; that is to say, between a spiritual fact and a mechanical and passive fact (not to say, between a concrete reality and an abstraction or fiction). In common speech, sometimes it is the words of the poet that are called _expressions,_ the notes of the musician, or the figures of the painter; sometimes the blush which generally accompanies the feeling of shame, the pallor often due to fear, the grinding of the teeth proper to violent anger, the shining of the eyes and certain movements of the muscles of the mouth, which manifest cheerfulness. We also say that a certain degree of heat is the _expression_ of fever, that the falling of the barometer is the _expression_ of rain, and even that the height of the exchange _expresses_ the depreciation of the paper currency of a State, or social discontent the approach of a revolution. One can well imagine what sort of scientific results would be attained by allowing oneself to be governed by verbal usage and classing together facts so widely different. But there is, in fact, an abyss between a man who is the prey of anger with all its natural manifestations and another