The influence of custom on our ideas of beauty is very great. For whenever two objects have been seen in frequent conjunction together, the imagination acquires a habit of passing easily from the one to the other; and thus, from the mere habit of expecting to see one when we see the other, though there should be no real beauty in their union, we are conscious of an impropriety when they chance to be separated. If even a suit of clothes is without some insignificant but usual ornament, such as a button, we are in some measure displeased by its absence.
The fashion of things changes with a rapidity proportioned to the durableness of their material. The modes of furniture change less rapidly than those of dress, because furniture is generally more durable; but in five or six years it generally undergoes a complete revolution, and every man sees its fashion change in many different ways even in his own lifetime. But the productions of such arts as music, poetry, or architecture, being much more lasting, the fashion or custom, which prevails no less over them than over whatever else is the object of taste, may continue unchanged for a much longer time. A building may endure for ages, a beautiful air may be handed down through generations, a poem may last as long as the world, and thus they may all set the fashion of their particular style or taste much longer than the design of a particular mode of dress or furniture.
It is only because of the greater permanence of their fashion, which prevents our having much experience of any change in them, that makes it less easy for us to recognize that the rules we think ought to be observed in each of the fine arts are no more founded on reason and the nature of things than they are in the matter of our furniture and dress.
In architecture, for instance, no reason can be assigned beyond habit and custom for the propriety of attaching to each of the five orders their peculiar ornaments. The eye, having been used to associate a certain ornamentation with a certain order, would be offended at missing their conjunction; but it is inconceivable that, prior to established custom, five hundred other forms should not have suited those proportions equally well.
It is the same in poetry. The ancients thought that a certain species of verse was by nature appropriated to a particular species of writing, according to the sentiment or character intended to be described. One kind of verse was fit for grave and another for gay themes, nor could either be interchanged without the greatest impropriety. Yet that which is the verse of burlesque in English is the heroic verse in French, simply because "custom has made the one nation associate the ideas of gravity, sublimity, and seriousness with that measure which the other has connected with whatever is gay, flippant, and ludicrous."Custom influences our judgment no less with regard to the beauty of natural objects; and the proportions which we admire in one kind of animal are quite different from those we admire in another. Every class of things has a beauty of its own, distinct from that of every other species.
Adam Smith stops short, however, of adopting the theory, so ably advocated in the last century by the Jesuit Buffier, and followed by Sir Joshua Reynolds, that custom is the sole principle of beauty, and that the beauty of every object consists simply in that form and colour which is most moral in every particular class of things. According to Buffier, in each species of creatures, that form was most beautiful which bore the strongest character of the general fabric of its species, and had the strongest resemblance to the greater number of the individuals with which it was classed. Hence the most customary form was the most beautiful, and much practice was needed to judge of the beauty of distinct species of things, or to know wherein the middle or most usual form consisted. Hence, too, different ideas of beauty existed in different countries, where difference of climate produced difference of type. Adam Smith so far agrees with this doctrine as to acknowledge that there is scarcely any external form so beautiful as to please, if quite contrary to custom, nor any so deformed as not to be agreeable, if uniformly supported by it; but he also argues that, independently of custom, we are pleased by the appearance of the utility of any formby its fitness for the purposes for which it was intended. Certain colours, moreover, are more agreeable than others, even the first time they are beheld by us; and though he does not lay the same stress on smoothness as Burke did, who held that nothing was beautiful that was not smooth, he also admits that a smooth surface is naturally more agreeable than a rough one.
The influence of custom and fashion upon our ideas of beauty generally being so great as has been explained, what is their influence upon our ideas of beauty of conduct? To this the answer is, that their influence is perfectly similar in kind, though not so great, or rather less potent, over morals than it is over anything else. Although there is no form of external objects to which custom will not reconcile us, nor fashion render agreeable to us, the characters or the conduct of a Nero or a Claudius are what no custom can ever make agreeable, or other than the objects of our hatred or derision; for the sentiments of moral approbation and disapprobation are founded on the strongest passions of human nature, and, though they can be warpt, they can never be perverted.