We may begin by asking what, as a matter of fact, has been the arrangement of spaces to give aesthetic pleasure. The primitive art of all nations shows that it has taken the direction of symmetry about a vertical line. It might be said that this is the result of non-aesthetic influences, such as convenience of construction, technique, etc.

<1>It is clear that much of the symmetry appearing in primitive art is due (1) to the conditions of construction, as in the form of dwellings, binding patterns, weaving and textile patterns generally; (2) to convenience in use, as in the shapes of spears, arrows, knives, two-handled baskets or jars; (3) to the imitation of animal forms, as in the shapes of pottery, etc. On the other hand, (1) a very great deal of symmetrical ornament maintains itself AGAINST the suggestions of the shape to which it is applied, as the ornaments of baskets, pottery, and all rounded objects; and (2) all distortion, disintegration, degradation of pattern- motives, often so marked as all but to destroy their meaning, is in the direction of geometrical symmetry. The early art of all civilized nations shows the same characteristic. Now it might be said that, as there exists an instinctive tendency to imitate visual forms by motor impulses, the impulses suggested by the symmetrical form are in harmony with the system of energies of our bilateral organism, which is a system of double motor innervations, and thus fulfill our demand for a set of reactions corresponding to the organism as a whole. But we should then expect that all space arrangements which deviate from complete symmetry, and thus suggest motor impulses which do not correspond to the natural bilateral type, would fail to give aesthetic pleasure. Such, however, is not the case. Non-symmetrical arrangements of space are often extremely pleasing.

<1> The following is adapted from the author's Studies in Symmetry, Harvard Psych. Studies, vol i, 1902.

This contradiction disappears if we are able to show that the apparently non-symmetrical arrangement contains a hidden symmetry, and that all the elements of that arrangement contribute to bring about just that bilateral type of motor impulses which is characteristic of geometrical symmetry.

A series of experiments was arranged, in which one of two unequal lines of white on a black background being fixed in an upright position a certain distance from the centre, the other was shifted until the arrangement was felt to be pleasing. It was found that when two lines of different sizes were opposed, their relative positions corresponded to the relation of the arms of a balance, that is, a small line far from the centre was opposed by a large one near the centre. A line pointing out from the centre fitted this formula if taken as "heavy," and pointing in, if taken as "light." Similarly, objects of intrinsic interest and objects suggesting depth in the third dimension were "heavy" in the same interpretation. All this, however, did not go beyond the proof that all pleasing space- arrangements can be described in terms of mechanical balance. But what was this mechanical balance? A metaphor explains nothing, and no one will maintain that the visual representation of a long line weights more than a short one. Moreover, the elements in the balance were so far heterogeneous. The movement suggested by an idea had been treated as if equivalent to the movement actually made by the eye in following a long line; the intrinsic interest-that is, the ideal interest-of an object insignificant in form was equated to the attractive power of a perspective, which has, presumably, a merely physiological effect on the visual mechanism.

I believe, however, that the justification of this apparent heterogeneity, and the basis for explanation, is given in the reduction of all elements to their lowest term,-as objects for the expenditure of attention. A large object and an "interesting" object are "heavy" for the same reason, because they call out the attention. And expenditure of effort is expenditure of attention; thus, if an object on the outskirts of the field of vision requires a wide sweep of the eye to take it in, it demands the expenditure of attention, and so is felt as "heavy." But what is "the expenditure of attention" in physiological terms? It is nothing more than the measure of the motor impulses directed to the object of attention. And whether the motor impulse appears as the tendency to follow out the suggestions of motion in the object, all reduces to the same physiological basis.

It may here be objected that our motor impulses are, nevertheless, still heterogeneous, inasmuch as some are toward the object of interest, and some along the line of movement. But it must be said, first, that these are not felt in the body, but transferred as values of weight to points in the picture,-it is the amount and not the direction of excitement that is counted; and secondly, that even if it were not so, the suggested movement along a line is felt as "weight" at a particular point.

From this point of view the justification of the metaphor of mechanical balance is quite clear. Given two lines, the most pleasing arrangement makes the larger nearer the centre, and the smaller far from it. This is balanced because the spontaneous impulse of attention to the near, large line equals in amount the involuntary expenditure to apprehend the small, farther one.

We may thus think of a space to be composed as a kind of target, in which certain spots or territories count more or less, both according to their distance from the centre and according to what fills them. Every element of a picture, in whatever way it gains power to excite motor impulses, is felt as expressing that power in the flat pattern. A noble vista is understood and enjoyed as a vista, but it is COUNTED in the motor equation, our "balance," as a spot of so much intrinsic value at such and such a distance from the centre. The skillful artist will fill his target in the way to give the maximum of motor impulses with the perfection of balance between them.

It is thus in a kind of substitutional symmetry, or balance, that we have the objective condition or counterpart of aesthetic repose, or unity. From this point of view it is clearly seen in what respect the unity of Hildebrand fails. He demands in the statue, especially, but also in the picture, the flat surface as a unity for the three dimensions. But it is only with the flat space, won, if you will, by Hildebrand's method, that the problem begins. Every point in the third dimension counts, as has been said, in the flat. The Fernbild is the beginning of beauty, but within the Fernbild favorable stimulation and repose must still be sought. And repose or unity is given by symmetry, subjectively the balance of attention, inasmuch as this balance is a tension of antagonistic impulses, an equilibrium, and thus an inhibition of movement.

From this point of view, we are in a position to refute Souriau's interesting analysis<1> of form as the condition for the appreciation of content. He says that form, in a picture for instance, has its value in its power to produce (through its fixation and concentration of the eye) a mild hypnosis, in which, as is well known, all suggestions come to us with bewildering vividness. This is, then, just the state in which the contents of the picture can most vividly impress themselves. Form, then, as the means to content, by giving the conditions for suggestion, is Sourieau's account of it. In so far as form-in the sense of unity-gives, through balance and equilibrium of impulses, the arrest of the personality, it may indeed be compared with hypnotism. But this arrest is not only a means, but an end in itself; that aesthetic repose, which, as the unity of the personality, is an essential element of the aesthetic emotion as we have described it.

<1> La Suggestion en l'Art.