By the power, however, which we have over the occasions of our sensations, we can make sure of having a train of sensations exactly the same as we have had before. This affords us the means of having a train of ideas exactly the same as we have had before. If we choose a number of sensible objects, and make use of them as marks of our ideas, we can ensure any succession which we please of the sensible objects; and, by the association between them and the ideas, a corresponding succession of the ideas. 6. To one of the two sets of occasions, upon which Signs are thus useful, _evanescent_ Signs are the best adapted; _permanent_ signs are absolutely necessary for the other. For the purposes of speech, or immediate communication, sounds are the most convenient marks. Sounds, however, perish in the making. But for the purpose of retracing a train of ideas, which we have formerly had, it is necessary we should have marks which do not perish. Marks, addressed to the sight, or the touch, have the requisite permanence; and, of the two, those addressed to the eye have the advantage. Of marks addressed to the eye, two kinds have been adopted; either marks immediately of the ideas intended to be recalled; such as the picture-writing, or hieroglyphics, of some nations: or, visible marks, by letters, of the audible marks employed in oral communication. This latter kind has been found the most convenient, and in use among the largest, and most intelligent portion of our species. {133} According to this scheme, spoken language is the use of immediate marks of the ideas; written language, is the use of secondary marks of the ideas. The written marks are only signs of the audible marks; the audible marks, are signs of the ideas.[40] [Editor's footnote 40: This exposition of Naming in its most general aspect, needs neither explanation nor comment. It is one of those specimens of clear and vigorous statement, going straight to the heart of the matter, and dwelling on it just long enough and no longer than necessary, in which the Analysis abounds.--_Ed._] {134} SECTION I. NOUNS SUBSTANTIVE. The power of Language essentially consists, in two things; first, in our having marks of our SENSATIONS, and IDEAS: and, secondly, in so arranging them, that they may correctly denote a TRAIN of those mental states or feelings. It is evident, that if we convey to others the ideas which pass in our own minds, and also convey them in the order in which they pass, the business of COMMUNICATION is completed. And, if we establish the means of reviving the ideas which we have formerly had, and also of reviving them in the order in which we formerly had them, the business of RECORDATION is completed. We now proceed to show, by what contrivances, the expedient of Marking is rendered efficient to those several ends.