Most writers on proverbs have thought it necessary to attempt a definition of their subject, but the task is difficult, and the phrase that will silence criticism has yet to be produced. Lord Russell's epigram describing a proverb as "The wisdom of many and the wit of one" is as good as any, but it leaves so much unsaid that as a definition it is certainly inadequate. On the other hand, it is a true remark, and the facts it emphasises may conveniently be taken as the point from which to begin this study.

No saying is a proverb until it has commended itself to a number of men; the wisdom of one is not a proverb, but the wisdom of many. Countless fine expressions well suited to become proverbial have perished in the speaking, or lie forgotten in our books. To win wide acceptance and then to keep pace with the jealous years and remain a living word on the lips of the people is an achievement few human thoughts have compassed; for thousands that pass unheeded only one here or there, helped by some happy quality, or perhaps some freak of fortune, is caught from mouth to mouth, approved, repeated and transmitted. Every accepted proverb has therefore survived a searching test, all the more severe because judgment is not always passed upon the merits of the case. Popular favour is at the best capricious, and often an admirable saying has died out of use and a worse become famous.