Having with wary steps traced an intricate road, not without danger of wandering; what remains to complete our journey, is to account for the final cause of congruity and propriety, which make so great a figure in the human constitution. One final cause, regarding congruity, is pretty obvious. The sense of congruity, as one of the principles of the fine arts, contributes in a remarkable degree to our entertainment. This is the final cause assigned above for our sense of proportion[6], and need not be enlarged upon here. Congruity indeed with respect to quantity, coincides with proportion. When the parts of a building are nicely adjusted to each other, it may be said indifferently, that it is agreeable by the congruity of its parts, or by the proportion of its parts. But propriety, which regards voluntary agents only, can never in any instance be the same with proportion. A very long nose is disproportioned, but cannot be termed _improper_. In some instances, it is true, impropriety coincides with disproportion in the same subject, but never in the same respect. I give for an example a very little man buckled to a long toledo. Considering the man and the sword with respect to size, we perceive a disproportion. Considering the sword as the choice of the man, we perceive an impropriety. The sense of impropriety with respect to mistakes, blunders, and absurdities, is happily contrived for the good of mankind. In the spectators it is productive of mirth and laughter, excellent recreation in an interval from business. The benefit is still more extensive. It is not agreeable to be the subject of ridicule; and to punish with ridicule the man who is guilty of an absurdity, tends to put him more upon his guard in time coming. Thus even the most innocent blunder is not committed with impunity; because, were errors licensed where they do no hurt, inattention would grow into a habit, and be the occasion of much hurt.