49. The earliest bond of union between objects of thought, is their being present ed to the mind together, or in close suc cession, through the medium of sensation ; this is owing to the objects of sensation being connected either in time or place, or iii other words, owing to the relation of contiguity in time and place existing between these objects. This cause of connection among our ideas is what ne cessarily has the earliest efficacy in Form ing those connections, because it does not presuppose, as every other does, the ex istence of other ideas in the mind, or the exercise of attention to other relations which exist among them. Children asso ciate ideas together almost entirely by this bond of union ; persons of uncultivat ed minds, in the same manner, usually have their ideas connected by the same bond of union, contiguity of time and place of the objects of sensation, producing im pressions on the mind at the same time, or in close succession ; and more or less it is a connecting link, or cause of connection, in every one, in every period of life. We might, d priori, calculate upon its high importance in the mental structure, and as a matter of fact, it is the foundation of all experience and philosophy, and at the same time the source of numerous dices. It is the source of numerous pre judices, by leading us to expect continued conjunction in time or place, where the conjunction was only occasional, and thus to suppose a real and permanent connec tion between objects which had only an accidental and temporary connection. Hence unenlightened experience of the past will fill the mind, in numberless in stances, with vain expectations, or with groundless alarms concerning the future ; hence the regard which is paid to unlucky days, to unlucky colours, to the influence of the planets, &c.; apprehensions which render human life, to many, a continual series of absurd terrors. But this prin ciple of connection among our ideas is also the foundation of all experience and philosophy ; for the grand object of philo phy is the knowledge of those laws which regulate the succession of events, so that from the past we may be enabled to anti cipate the probable course of the future, and to regulate our conduct accordingly ; and therefore it is of the first importance that the connections of time and place should have a strong power over the mind. Experience is of a more limited nature, but has the same object to anticipate the probable course of events, so as to make the past subservient to the conduct of the future ; and by rendering contiguity, in time, one of the strongest principles of connection in our minds; the wise Au thor of our frame has conjoined in our thoughts the same events which we find conjoined in our experience, and has thus accommodated (without any effort on our part) the order of our ideas to that scene in which we are destined to act.
50. Upon the connections established by this principle, all other connections are founded. Some of the most striking are those which arise from the relations of similarity, of contrariety, of cause and effect, of means and end, of premises and conclusion. Next to the relation of con tiguity in time and place, that of similari ty is most universally operative, It does not depend upon an active exertion of intellect, but arises spontaneously from the mental constitution. Similarity im plies partial identity of sensation, and hence an object, when first presented to the mind, frequently recals the idea of that which has some parts of its component sensations the same. Thus when we see a face which considerably interests us, we are often led to recollect the face of some other person, in consequence of the impressions from each agreeing in some particulars. In the same manner, where the circumstances of one event are, in some respects, the same with the circumstances of another, which had be fore fallen under our notice, so far there is a recurrence of the same impressions, and that by the more general law of association recals the remaining cir cumstances.—This cause of connection among our ideas, like that of contiguity in time or place, is of the greatest impor portance, and at the same time liable to be greatly misused. Without it the expe rience of the past would be of no utility to us, for the same set of circumstances never occurs twice ; if there be sufficient similarity to recal the past, it now answers the purpose of exciting the expectations of what occurred in similar circumstances, that is, of bringing the experience of the past to bear upon, the present. But as
similarity is only partial sameness, if it be not accompanied with some discrimi nation, consequences will be expected that will never happen, and conclusions, which will mislead, will be formed with out any just foundation.—Ideas are con nected together not only in consequence of similarity, that is, sameness in some of their component parts, but frequently also from similarity in the sounds express ing them. It is upon this circumstance that the art of punning is founded ; an art which may be innocent in itself con sidered, but which, when made an ob ject of the mind, leads from sense to sound, and prevents us from carefully ex amining the arguments and differences of things, on which alone reasoning can be founded. So much, indeed, is a habit of punning at variance with habits of thought and sober reflection, that the whole cur rent of thought will sometimes be divert ed from its proper channel, by some word in which the thought is expressed, re calling, by similarity of sound, some other which calls up its own train of thought. A. good pun may sometimes be ed as an exercise of. the judgment; but more usually it is merely an exercise of the associajive power ; in this particular principle of connection, similarity in sound ; and therefore it would be wise in young persons to check the desire to obtain an acquisition which is of little value, because almost every one may ac quire it, and which must check the cul ture of other more valuable principles of association.
51. Another fertile principle of tion is contrariety, which connects to gether ideas which are totally, or in many respects opposite to each other. This, however, is more the result of attention and habit than those of contiguity in time or place, and similarity. Some persons are particularly disposed to it, others have little tendency to it. It frequently appears to arise from the natural tenden cy of the mind to change from one set of feelings, which are in some way or other displeasing, to others which may be pleasing ; and very often serves to il lustrate reasoning ; but particularly to give interest and force to a description of natural scenery, or a delineation of character.
52. The other principles of connection which we mentioned are more refined, and are the result of culture. A person who has been more accustomed to philo sophize, or to reason, than to follow the airy flights of wit or poetic fancy, con nects his ideas by the principles of cause and effect, of means and end, of premises and conclusion. When a phenomenon is stated to his mind, it almost involuntarily brings. forward ideas which serve to ac count for the phenomenon : we do not mean, that the mind invariably brings forward the right ideas, but simply those which answer the wants of the individu al, by serving to account to him for the phenomenon. So, in the same manner, when an end is proposed, the train of thought is concerned about the means, which are often suggested, though the object itself was never before in the view of the mind. All these relations doubt less produce their effect by minute and almost imperceptible samenesses in the particular object now in the view of the mind, and some one which before has been, and has been connected by some cause or other with the cause or means by which it was produced, or to be produced ; but it is convenient to speak of them as distinct from the more obvious relations, because they imply different culture of the mind, and lead to such widely differ ent effects.—Now any one of these con necting principles may, by habit, be strengthened to such a degree as to give us a command over all the different ideas in our mind which have the given rela tion to each other ; so that when any one in the class occurs to us, we have almost a certainty that it will suggest the rest.—As this appears to be an in disputable fact respecting the influence of association, we may state it in the fol lowing general form :—When an idea is presented to the mind, either by sensa tion or by association, bearing certain relations, either in itself, or in its effects ore the mind, with another idea already on the mind, the latter is recalled by the former, and becomes connected with it : and the association thus produced is subject to the same laws with those formed, owing to the contiguity in the times of the reception of the ideas.