2. Whenever two or more impressions or ideas have something in common that is appreciable, they are in harmony, in the measure of what they have in common. The harmony increases as the common element increases; or the common elements. It diminishes in the measure of every difference or contrast. By the Order of Harmony I mean some recurrence or repetition, some correspondence or likeness. The likeness may be in sounds or in sights, in muscular or other sense-impressions. It may lie in sensations, in perceptions, in ideas, in systems of thought.
THE ORDER OF BALANCE
3. By the Order of Balance I mean some equal opposition and consequent equilibrium, as it occurs at some moment of Time or at some point of Space; an equilibrium which induces, for the moment and in its place, a suspension of all change or movement, and causes a pause or a rest. The equilibrium may be one of physical forces (forces of weight or resistance) or forces of will. It may be an equilibrium of sense-impressions or attractions, of interests, of alternative propositions or ideas. It may be the equilibrium of a perfect antithesis. Certain moments of Time, certain points of Space, are distinguished from others by instances of equilibrium or balance. The balance being lost, in any case, we have at once some movement. If this movement is regular, and marked in its regularity, we get, instead of Balance, Rhythm.
THE ORDER OF RHYTHM
4. By the Order of Rhythm I mean changes of sensation; changes in muscular impressions as we feel them, in sounds as we hear them, in sights as we see them; changes in objects, people, or things as we know them and think of them, changes which induce the feeling or idea of movement, either in the duration of Time or in the extension of Space; provided that the changes take place at regular and marked intervals of time or in regular and marked measures of space. By regular intervals and measures I mean equal or lawfully varying intervals and measures. I do not mean, by Rhythm, changes simply, inducing the sense or idea of movement: I mean, by Rhythm, a regularity of changes in a regularity of measures, with the effect of movement upon our minds.
Rhythms in Time differ from Rhythms in Space, inasmuch as the movement in Time is in one direction, inevitably. It lies in the duration and passing of time, from which nothing escapes. The movement in space, on the contrary, may be in any one of many possible directions. A movement in different directions, particularly in contrary directions, amounts to a negation of movement. In any space-rhythm, therefore, the direction in which the rhythm leads us, the direction in which we follow it, must be unmistakable.
5. Of these three principles of Order, the first and foremost, the most far-reaching and comprehensive, is the principle of Harmony. We have Harmony in all balances, and we have it also in all rhythms. It is, therefore, undesirable to think of the three principles as coördinate. It will be better to think of the principle of Harmony first, and then of two other principles, those of Balance and of Rhythm, as lying within the range of Harmony but not coextensive with it. We might express the idea in a logical diagram.
Fig. 1
Within the field of Harmony we have two distinct modes of Order—Balance and Rhythm; but we have Harmony beyond the range of Balance and beyond the range of Rhythm.