sciences is chiefly carried on by the new significations given to words in this third way. The fourth by converting the reader into a writer, helps him to be expert in distinguishing, quick in recollecting, and faithful in retaining, these new significations of words, being the inverse of the third method, as just now remarked. The reader will easily see, that the action of the hand is not an essential in this fourth method. Composition by persons born blind has nearly the same effect. I mention it as being the common attendant upon composition, as having a considerable use deducible from association, and as making the analogy between the four methods more conspicuous and complete.
This may suffice, for the present, to prove the first part of the proposition; viz. that words and phrases must excite ideas in us by association. The second part, or that they excite ideas in us by no other means, may appear at the same time, as it may be found upon reflection and examination, that all the ideas which any word does excite are deducible from some of the four sources above-mentioned, most commonly from the first or third.
It may appear also from the instances of the words of unknown languages, terms of art not yet explained, barbarous words, &c. of which we either have no ideas, or only such as some fancied resemblance, or prior association, suggests.
It is highly worthy of remark here, that articulate sounds are by their variety, number, and ready use, particularly suited to signify and suggest, by association, both our simple ideas, and the complex ones formed from them, according to the twelfth proposition.
Cor. It follows from this proposition, that the arts of logic and rational grammar depend entirely on the doctrine of association. For logic, considered as the art of thinking or reasoning, treats only of such ideas as are annexed to words; and, as the art of discoursing, it teaches the proper use of words in a general way, as grammar does in a more minute and particular one.
This may be done by applying the doctrine of association, as laid down in the first chapter, to words, considered in the four lights mentioned under the last proposition.
First, then, The association of the names of visible objects, with the impressions which these objects make upon the eye, seems to take place more early than any other, and to be effected in the following manner: the name of the visible object, the nurse, for instance, is pronounced and repeated by the attendants to the child, more frequently when his eye is fixed upon the nurse, than when upon other objects, and much more so than when upon any particular one. The word nurse is also sounded
