There are two purposes, both of great importance, for which marks of our ideas, and sensations; or signs by which they may be denoted; are necessary. One of these purposes is, That we maybe able to make known to others what passes within us. The other is, That we may secure to ourselves the knowledge of what at any preceding time has passed in our minds.

The sensations and ideas of one man are hidden from all other men; unless they have recourse to some expedient for disclosing them. We cannot convey to another man our sensations and ideas directly. Our means of intercourse with other men are through their senses exclusively. We must therefore choose some SENSIBLE OBJECTS, as SIGNS of our inward feelings. If two men agree, that each shall use a certain sensible sign, when one of them means to make known to the other that he has a certain sensation, or idea, they, in this, and in no other way, can communicate a knowledge of those feelings to one another.

Almost all the advantages, which man possesses above the inferior animals, arise from his power of acting in combination with his fellows; and of accomplishing, by the united efforts of numbers, what could 129 not be accomplished by the detached efforts of individuals. Without the power of communicating to one another their sensations and ideas, this co-operation would be impossible. The importance, therefore, of the invention of signs, or marks, by which alone that communication can be effected, is obvious.

Among sensible objects, those alone which are addressed to the senses of seeing and hearing have sufficient precision and variety to be adapted to this end. The language of Action, as it has been called, that is, certain gesticulations and motions, has very generally, especially among rude people, whose spoken language is scanty, been found in use to indicate certain states, generally complicated states, of mind. But, for precision, variety, and rapidity, the flexibility of the voice presented such obvious advantages, not to mention that visible signs must be altogether useless in the dark, that sounds, among all the varieties of our species, have been assumed as the principal medium by which their sensations and ideas were made known to one another.

There can be little doubt that, of the two uses of marks, Communicating our thoughts, and Recording them, the advantage of the first would be the earliest felt; and that signs for Communicating would be long invented, before any person would see the advantage of Recording his thoughts. After the use of signs for Communication had become familiar, it would not fail, in time, to appear that signs might be employed for Recordation also; and that, from this use of them, the highest advantages might be derived.

In respect to those advantages, the following particulars are to be observed.

130 1. We cannot recall any idea, or train of ideas, at will. Thoughts come into the mind unbidden. If they did not come unbidden, they must have been in the mind before they came into it; which is a contradiction. You cannot bid a thought come into the mind, without knowing that which you bid; but to know a thought is to have the thought: the knowledge of the thought, and the thought’s being in the mind, are not two things but one and the same thing, under different names.

If we cannot recall at pleasure a single idea, we are not less unable to recall a train. Every person knows how evanescent his thoughts are, and how impossible it is for him to begin at the beginning of a past train, if it is not a train of the individual objects familiar to his senses, and go on to the end, neither leaving out any of the items which composed it, nor allowing any which did not belong to it, to enter in.

2. It is most obvious that, by ideas alone, the events which are passed, are to us any thing. If the objects which we have seen, heard, smelt, tasted, and touched, left no traces of themselves; if the immediate sensation were every thing, and a blank ensued when the sensation ended, the past would be to us as if it had never been. Yesterday would be as unknown as the months we passed in the womb, or the myriads of years before we were born.

3. It is only by our ideas of the past, that we have any power of anticipating the future. And if we had no power of anticipating the future, we should have no principle of action, but the physical impulses, which we have in common with the brutes. This great law of our nature, the anticipation of the future from the 131 past, will be fully illustrated in a [subsequent] part of this inquiry: at present, all that is required is, the admission, which will probably not be refused, of this general truth: That the order, in which events have been observed to take place, is the order in which they are expected to take place; that the order in which they have taken place is testified to us only by our ideas; and that upon the correctness, with which they are so testified, depends the faculty we possess of converting the powers of nature into the instruments of our will; and of bringing to pass the events which we desire.