The Theory of Moral Sentiments - Adam Smith [235]
Whatever were the difficulties, therefore, which embarrassed the first invention of nouns adjective, the same, and many more, must have embarrassed that of prepositions. If mankind, therefore, in the first formation of languages, seem to have, for some time, evaded the necessity of nouns adjective, by varying the termination of the names of substances, according as these varied in some of their most important qualities, they would much more find themselves under the necessity of evading, by some similar contrivance, the yet more difficult invention of prepositions. The different cases in the ancient languages is a contrivance of precisely the same kind. The genitive and dative cases, in Greek and Latin, evidently supply the place of the prepositions; and by a variation in the noun substantive, which stands for the co-relative term, express the relation which subsists between what is denoted by that noun substantive, and what is expressed by some other word in the sentence. In these expressions, for example, fructus arboris, the fruit of the tree; sacer Herculi, sacred to Hercules; the variations made in the co-relative words, arbor and Hercules, express the same relations which are expressed in English by the prepositions of and to.
To express a relation in this manner, did not require any effort of abstraction. It was not here expressed by a peculiar word denoting relation and nothing but relation, but by a variation upon the co-relative term. It was expressed here, as it appears in nature, not as something separated and detached, but as thoroughly mixed and blended with the co-relative object.
To express relation in this manner, did not require any effort of generalization. The words arboris and Herculi, while they involve in their signification the same relation expressed by the English prepositions of and to, are not, like those prepositions, general words, which can be applied to express the same relation between whatever other objects it might be observed to subsist.
To express relation in this manner did not require any effort of comparison. The words arboris and Herculi are not general words intended to denote a particular species of relations which the inventors of those expressions meant, in consequence of some sort of comparison, to separate and distinguish from every other sort of relation. The example, indeed, of this contrivance would soon probably be followed, and whoever had occasion to express a similar relation between any other objects would be very apt to do it by making a similar variation on the name of the co-relative object. This, I say, would probably, or rather certainly happen; but it would happen without any intention or foresight in those who first set the example, and who never meant to establish any general rule. The general rule would establish itself insensibly, and by slow degrees, in consequence of that love of analogy and similarity of sound, which is the foundation of by far the greater part of the rules of grammar.6
To express relation, therefore, by a variation in the name of the co-relative object, requiring neither abstraction nor generalization, nor comparison of any kind, would, at first, be much more natural and easy, than to express it by those general words called prepositions, of which the first invention must have demanded some degree of all those operations.
The number of cases is different in different languages. There are five in the Greek, six in the Latin, and there are said to be ten in the Armenian language. It must have naturally happened that there