188. A composite idea seems to be a union, or rather a connected series of ideas, which are either excited simultaneously, or follow each other with great rapidity. Our understanding requires words to bind this collection, to retain the thread which connects them; and hence it is, that when the idea is simple, language is not indispensable. It is said that speech is necessary in order to think, it might sometimes be said with more propriety, that it is necessary in order to _recollect_. 189. When the object occupying our attention is offered to the sensible intuition, we have no need of speech. We can, when we reflect upon a right line, an angle, a triangle, observe that their imaginary representation is all that we require, and that we do not need to bind these objects together by words. The same thing happens in thinking of unity, or on the numbers two, three, and four, which we easily represent to ourselves sensibly. The necessity for speech begins when the imagination loses the distinct representation of objects, and needs to combine various ideas. Did we not assign to a word the idea of a many-sided polygon, we should be in the greatest confusion, and it would be impossible for us to reason upon it. 190. Since, on the one hand, our perceptive faculties do not create their objects, but are limited to the combining of them; and, on the other hand, our perception is not capable of embracing many at one time, it results that the exercise of our faculties is necessarily successive; the unity of consciousness serving as the bond of union to our perceptions. But consciousness has no other means of knowing what passes within it, than to fix its operations by determinate signs, whence flows the necessity of arbitrary signs, which must be sensible, by reason of the relation uniting our intelligence with the sensitive faculties: and it is to be observed, that for this reason, every sign to which we assign an idea, may be the object of one of the senses. The great number and variety of ideas and their combinations, require an exceedingly variable and flexible sign, and this variety and flexibility require certain characters to simplify it, and thus render its retention in the memory more easy, whence the advantages of language: in the midst of its astonishing variety it lays these characters in radical syllables. The conjugation of a single verb alone offers us a considerable number of very different ideas, the retention of which would be excessively difficult, were they not joined by some tie such as the radical syllable: as in the verb to speak, the syllable speak. We see this by the greater labor the irregular verbs cost us than do the regular verbs when learning a language: and it may be remarked in children also, who blunder on the irregularities. We might compare language to the catalogue of a library, which is the more perfect, the more it unites simplicity with variety, so as to designate