a suitableness or relation of agreement between things.
The terms congruity and propriety are not applicable to any single object; they imply a plurality, and obviously signify a particular relation between different objects. Thus we are accustomed to say, that a decent garb is suitable or proper for a judge, modest behaviour for a young woman, and a lofty style for an epic poem; and, on the other hand, that it is unsuitable or incongruous to see a little woman sunk in an overgrown farthingale, a coat richly embroidered covering coarse and dirty linen, a mean subject in a pompous style, an elevated subject in mean language, a first minister darning his wife's stocking, or a reverend prelate in lawn sleeves dancing a hornpipe.
The perception we have of this relation, which seems peculiar to man, cannot proceed from any other cause than a sense of congruity or propriety; for, supposing us destitute of this sense, the terms would be to us unintelligible.
It is a matter of experience that congruity or propriety, wherever perceived, is agreeable; and that incongruity or impropriety, wherever perceived, is disagreeable. The only difficulty is to ascertain what are the particular objects which in conjunction suggest these relations; for there are many objects that do not. The sea, for example, viewed in conjunction with a picture, or a man viewed in conjunction with a mountain, suggest not either congruity or incongruity. It seems natural to infer, what indeed will be found true by induction, that we never perceive congruity or incongruity except among things which are connected together by some relation; such as a man and his actions, a principal and his accessories, a subject and its ornaments. We are indeed so framed by nature, that things thus connected require a certain suitableness or correspondence, termed congruity or propriety; and hence we feel displeasure when we discover the opposite relation of incongruity or impropriety.
If things connected be the subject of congruity, it is reasonable to expect that a degree of congruity proportioned to the degree of the connexion should be required; and, upon examination, we find this to be fact. Where the relation is intimate, as between a cause and its effect, a whole and its parts, we require the strictest congruity; but where the relation is slight or accidental, as among things jumbled together in the same place, we require little or no congruity. The strictest propriety is required in behaviour and manner of living, because a man is connected with these by the relation of cause and effect. The relation between an edifice and the ground it stands upon is of the most intimate kind; and, therefore, the situation of a great house ought to be lofty; its relation to neighbouring hills, rivers, plains, being that of propinquity only, demands but a small share of congruity. Among members of the same club the congruity ought to be considerable, as well as among things placed for show in the same niche; among passengers in a stage-coach we require very little congruity, and less still at a public spectacle.
Congruity is so nearly allied to beauty, as commonly to be held a species of it; and yet they differ so essentially as never to coincide. Beauty, like colour, is placed upon a single subject; congruity upon a plurality; and a thing beautiful in itself may, with relation to other things, produce the strongest sense of incongruity.
Congruity and propriety are commonly reckoned synonymous terms, but they are distinguishable, and the precise meaning of each must be ascertained. Congruity is the genus of which propriety is a species; for we call nothing proper, but that congruity or suitableness which ought to subsist between sensible beings and their thoughts, words, and actions.