As men have frequently occasion to make mention of multitudes as well as of single objects, it became necessary that they should have some method of expressing number. Number may be expressed either by a particular word, expressing number in general, such as the words _many_, _more_, &c. or by some variation upon the words which express the things numbered. It is this last expedient which mankind would probably have recourse to, in the infancy of language. Number, considered in general, without relation to any particular set of objects numbered, is one of the most abstract and metaphysical ideas, which the mind of man is capable of forming; and, consequently, is not an idea, which would readily occur to rude mortals, who were just beginning to form a language. They would naturally, therefore, distinguish when they talked of a single, and when they talked of a multitude of objects, not by any metaphysical adjectives, such as the English, _a_, _an_, _many_, but by a variation upon the termination of the word which signified the objects numbered. Hence the origin of the singular and plural numbers, in all the ancient languages; and the same distinction has likewise been retained in all the modern languages, at least, in the greater part of words. All primitive and uncompounded languages seem to have a dual, as well as a plural number. This is the case of the Greek, and I am told of the Hebrew, of the Gothic, and of many other languages. In the rude beginnings of society, _one_, _two_, and _more_, might possibly be all the numeral distinctions which mankind would have any occasion to take notice of. These they would find it more natural to express, by a variation upon every particular noun substantive, than by such general and abstract words as _one_, _two_, _three_, _four_, &c. These words, though custom has rendered them familiar to us, express, perhaps, the most subtile and refined abstractions, which the mind of man is capable of forming. Let any one consider within himself, for example, what he means by the word _three_, which signifies neither three shillings, nor three pence, nor three men, nor three horses, but three in general; and he will easily satisfy himself that a word, which denotes so very metaphysical an abstraction, could not be either a very obvious or a very early invention. I have read of some savage nations, whose language was capable of expressing no more than the three first numeral distinctions. But whether it expressed those distinctions by three general words, or by variations upon the nouns substantive, denoting the things numbered, I do not remember to have met with any thing which could determine.