Concerning the final cause of our taste for variety, it will be considered, that human affairs, complex by variety as well as number, require the distributing our attention and activity, in measure and proportion. Nature therefore, to secure a just distribution corresponding to the variety of human affairs, has made too great uniformity or too great variety in the course of our perceptions equally unpleasant. And indeed, were we addicted to either extreme, our internal constitution would be ill suited to our external circumstances. At the same time, where a frequent reiteration of the same operation is required, as in several manufactures, or a quick circulation, as in law or physic, Nature, attentive to all our wants, hath also provided for these cases. She hath implanted in the breast of every person, an efficacious principle, which leads to habit. By an obstinate perseverance in the same occupation, the pain of excessive uniformity vanisheth; and by the like perseverance in a quick circulation of different occupations, the pain of excessive variety vanisheth. And thus we come to take delight in several occupations, that by nature, without habit, are not a little disgustful. A middle rate also in our train of perceptions betwixt uniformity and variety, is not less pleasant, than betwixt quickness and slowness. The mind of man thus constituted, is wonderfully adapted to the course of human affairs, which are continually changing, but not without connection. It is equally adapted to the acquisition of knowledge, which results chiefly from discovering resemblances among differing objects, and differences among resembling objects. Such occupation, even abstracting from the knowledge we acquire, is in itself delightful, by preserving a middle rate betwixt too great uniformity and too great variety. We are now arrived at the chief purpose of the present chapter; and that is to examine how far uniformity or variety ought to be studied in the fine arts. And the knowledge we have obtained, will even at first view suggest a general observation, That in every work of art, it must be agreeable to find that degree of variety which corresponds to the natural course of our perceptions; and that an excess in variety or in uniformity, must be disagreeable by varying that natural course. For this reason, works of art admit more or less variety according to the nature of the subject. In a picture that strongly attaches the spectator to a single object, the mind relisheth not a multiplicity of figures or of ornaments. A picture again representing a gay subject, admits great variety of figures and ornaments; because these are agreeable to the mind in a chearful tone. The same observation is applicable to poetry and to music.