unknown quantities in algebra, being determinable and decypherable, as one may say, only by means of the known words with which they are joined.
Thus I walk is associated at different times with the same visible impression as nurse walks, brother walks, &c. and therefore can suggest nothing permanently for a long time but the action of walking. However the pronoun I, in this and innumerable other short sentences, being always associated with the person speaking, as thou is with the person spoken to, and he with the person spoken of, the frequent recurrency of this teaches the child the use of the pronouns, i.e. teaches him what difference he is to expect in his sensible impressions according as this or that pronoun is used; the infinite number of instances, as one may say, making up for the infinitely small quantity of information, which each, singly taken, conveys.
In like manner, different particles, i.e. adverbs, conjunctions, and prepositions, being used in sentences, where the substantives, adjectives, and verbs, are the same, and the same particles, where these are different, in an endless recurrency, teach children the use of the particles in a gross general way. For it may be observed, that children are much at a loss for the true use of the pronouns and particles for some years, and that they often repeat the proper name of the person instead of the pronoun; which confirms the foregoing reasoning. Some of the inferior parts or particles of speech make scarce any alteration in the sense of the sentence, and therefore are called expletives. The several terminations of the Greek and Latin nouns and verbs are of the nature of pronouns and particles.
Eighthly, The attempts which children make to express their own wants, perceptions, pains, &c. in words, and the corrections and suggestions of the attendants, are of the greatest use in all the steps that we have hitherto considered, and especially in the last, regarding the pronouns and particles.
Ninthly, Learning to read helps children much in the same respects; especially as it teaches them to separate sentences into the several words which compound them; which those who cannot read are scarce able to do, even when arrived at adult age.
Thus we may see, how children and others are enabled to understand a continued discourse relating to sensible impressions only, and how the words in passing over the ear must raise up trains of visible and other ideas by the power of association. Our next inquiry must be concerning the words that denote either intellectual things, or collections of other words.
Tenthly, The words that relate to the several passions of love, hatred, hope, fear, anger, &c. being applied to the child at the times when he is under the influence of these passions, get the power of raising the miniatures or ideas of these passions, and also of the usual associated circumstances. The application of
