be made by common consent, and must have been effected in a manner not very easy for men whose gross organs had not been accustomed to any such exercise. It is also in itself still more difficult to conceive, since such a common agreement must have had motives, and speech seems to have been highly necessary to establish the use of it.
It is reasonable to suppose that the words first made use of by mankind had a much more extensive signification than those used in languages already formed, and that ignorant as they were of the division of discourse into its constituent parts, they at first gave every single word the sense of a whole proposition. When they began to distinguish subject and attribute, and noun and verb, which was itself no common effort of genius, substantives were first only so many proper names; the present infinitive was the only tense of verbs; and the very idea of adjectives must have been developed with great difficulty; for every adjective is an abstract idea, and abstractions are painful and unnatural operations.
Every object at first received a particular name without regard to genus or species, which these primitive originators were not in a position to distinguish; every individual presented itself to their minds in isolation, as they are in the picture of nature. If one oak was called A, another was called B; for the primitive idea of two things is that they are not the same, and it often takes a long time for what they have in common to be seen: so that, the narrower the limits of their knowledge of things, the more copious their dictionary must have been. The difficulty of using such a vocabulary could not be easily removed; for, to arrange beings under common and generic denominations, it became necessary to know their distinguishing properties: the need arose for observation and definition, that is to say, for natural history and metaphysics of a far more developed kind than men can at that time have possessed.
Add to this, that general ideas cannot be introduced into the mind without the assistance of words, nor can the understanding seize them except by means of propositions. This is one of the reasons why animals cannot form such ideas, or ever acquire that capacity for self-improvement which depends on them. When a monkey goes from one nut to another, are we to conceive that he entertains any general idea
