Beauty hath usually been said to consist in certain proportions of parts. On considering the matter, I have great reason to doubt, whether beauty be at all an idea belonging to proportion. Proportion relates almost wholly to convenience, as every idea of order seems to do; and it must therefore be considered as a creature of the understanding, rather than a primary cause acting on the senses and imagination. It is not by the force of long attention and inquiry that we find any object to be beautiful; beauty demands no assistance from our reasoning; even the will is unconcerned; the appearance of beauty as effectually causes some degree of love in us, as the application of ice or fire produces the ideas of heat or cold. To gain something like a satisfactory conclusion in this point, it were well to examine what proportion is; since several who make use of that word do not always seem to understand very clearly the force of the term, nor to have very distinct ideas concerning the thing itself. Proportion is the measure of relative quantity. Since all quantity is divisible, it is evident that every distinct part into which any quantity is divided must bear some relation to the other parts, or to the whole. These relations give an origin to the idea of proportion. They are discovered by mensuration, and they are the objects of mathematical inquiry. But whether any part of any determinate quantity be a fourth, or a fifth, or a sixth, or a moiety of the whole; or whether it be of equal length with any other part, or double its length, or but one half, is a matter merely indifferent to the mind; it stands neuter in the question: and it is from this absolute indifference and tranquillity of the mind, that mathematical speculations derive some of their most considerable advantages; because there is nothing to interest the imagination; because the judgment sits free and unbiassed to examine the point. All proportions, every arrangement of quantity, is alike to the understanding, because the same truths result to it from all; from greater, from lesser, from equality and inequality. But surely beauty is no idea belonging to mensuration; nor has it anything to do with calculation and geometry. If it had, we might then point out some certain measures which we could demonstrate to be beautiful, either as simply considered, or as related to others; and we could call in those natural objects, for whose beauty we have no voucher but the sense, to this happy standard, and confirm the voice of our passions by the determination of our reason. But since we have not this help, let us see whether proportion can in any sense be considered as the cause of beauty, as hath been so generally, and, by some, so confidently affirmed. If proportion be one of the constituents of beauty, it must derive that power either from some natural properties inherent in certain measures, which operate mechanically; from the operation of custom; or from the fitness which some measures have to answer some particular ends of conveniency.

Our business therefore is to inquire, whether the parts of those objects, which are found beautiful in the vegetable or animal kingdoms, are constantly so formed according to such certain measures, as may serve to satisfy us that their beauty results from those measures, on the principle of a natural mechanical cause; or from custom; or, in fine, from their fitness for any determinate purposes. I intend to examine this point under each of these heads in their order. But before I proceed further, I hope it will not be thought amiss, if I lay down the rules which governed me in this inquiry, and which have misled me in it, if I have gone astray. 1. If two bodies produce the same or a similar effect on the mind, and on examination they are found to agree in some of their properties, and to differ in others; the common effect is to be attributed to the properties in which they agree, and not to those in which they differ. 2. Not to account for the effect of a natural object from the effect of an artificial object. 3. Not to account for the effect of any natural object from a conclusion of our reason concerning its uses, if a natural cause may be assigned. 4. Not to admit any determinate quantity, or any relation of quantity, as the cause of a certain effect, if the effect is produced by different or opposite measures and relations; or if these measures and relations may exist, and yet the effect may not be produced.

These are the rules which I have chiefly followed, whilst I examined into the power of proportion considered as a natural cause; and these, if he thinks them just, I request the reader to carry with him throughout the following discussion; whilst we inquire, in the first place, in what things we find this quality of beauty; next, to see whether in these we can find any assignable proportions in such a manner as ought to convince us that our idea of beauty results from them. We shall consider this pleasing power as it appears in vegetables, in the inferior animals, and in man. Turning our eyes to the vegetable creation, we find nothing there so beautiful as flowers; but flowers are almost of every sort of shape, and of every sort of disposition; they are turned and fashioned into an infinite variety of forms; and from these forms botanists have given them their names, which are almost as various. What proportion do we discover between the stalks and the leaves of flowers, or between the leaves and the pistils? How does the slender stalk of the rose agree with the bulky head under which it bends? but the rose is a beautiful flower; and can we undertake to say that it does not owe a great deal of its beauty even to that disproportion; the rose is a large flower, yet it grows upon a small shrub; the flower of the apple is very small, and grows upon a large tree; yet the rose and the apple blossom are both beautiful, and the plants that bear them are most engagingly attired, notwithstanding this disproportion. What by general consent is allowed to be a more beautiful object than an orange-tree, nourishing at once with its leaves, its blossoms, and its fruit? but it is in vain that we search here for any proportion between the height, the breadth, or anything else concerning the dimensions of the whole, or concerning the relation of the particular parts to each other. I grant that we may observe in many flowers something of a regular figure, and of a methodical disposition of the leaves. The rose has such a figure and such a disposition of its petals; but in an oblique view, when this figure is in a good measure lost, and the order of the leaves confounded, it yet retains its beauty; the rose is even more beautiful before it is full blown; in the bud; before this exact figure is formed; and this is not the only instance wherein method and exactness, the soul of proportion, are found rather prejudicial than serviceable to the cause of beauty.