Section VIII. Of the causes of belief.
HAVING thus explained the nature of belief, and shown that it consists in a lively idea related to a present impression; let us now proceed to examine from what principles it is derived, and what bestows the vivacity on the idea.
I would willingly establish it as a general maxim in the science of human nature, that when any impression becomes present to us, it not only transports the mind to such ideas as are related to it, but likewise communicates to them a share of its force and vivacity. All the operations of the mind depend in a great measure on its disposition, when it performs them; and according as the spirits are more or less elevated, and the attention more or less fixed, the action will always have more or less vigour and vivacity. When therefore any object is presented, which elevates and enlivens the thought, every action, to which the mind applies itself, will be more strong and vivid, as long as that disposition continues. Now 'tis evident the continuance of the disposition depends entirely on the objects, about which the mind is employed; and that any new object naturally gives a new direction to the spirits, and changes the disposition; as on the contrary, when the mind fixes constantly on the same object, or passes easily and insensibly along related objects, the disposition has a much longer duration. Hence it happens, that when the mind is once enlivened by a present impression, it proceeds to form a more lively idea of the related objects, by a natural transition of the disposition from the one to the other. The change of the objects is so easy, that the mind is scarce sensible of it, but applies itself to the conception of the related idea with all the force and vivacity it acquired from the present impression.
If in considering the nature of relation, and that facility of transition, which is essential to it, we can satisfy ourselves concerning the reality of this phenomenon, 'tis well: But I must confess I place my chief confidence in experience to prove so material a principle. We may, therefore, observe, as the first experiment to our present purpose, that upon the appearance of the picture of an absent friend, our idea of him is evidently enlivened by the resemblance, and that every passion, which that idea occasions, whether of joy or sorrow, acquires new force and vigour. In producing this effect there concur both a relation and a present impression. Where the picture bears him no resemblance, or at least was not intended for him, it never so much as conveys our thought to him: And where it is absent, as well as the person; tho' the mind may pass from the thought of the one to that of the other; it feels its idea to be rather weakened than enlivened by that transition. We take a pleasure in viewing the picture of a friend, when 'tis set before us; but when 'tis removed, rather choose to consider him directly, than by reflection in an image, which is equally distinct and obscure.
The ceremonies of the Roman Catholic religion may be considered as experiments of the same nature. The devotees of that strange superstition usually plead in excuse of the mummeries, with which they are upbraided, that they feel the good effect of those external motions, and postures, and actions, in enlivening their devotion, and quickening their fervor, which otherwise would decay away, if directed entirely to distant and immaterial objects. We shadow out the objects of our faith, say they, in sensible types and images, and render them more present to us by the immediate presence of these types, than 'tis possible for us to do, merely by an intellectual view and contemplation. Sensible objects have always a greater influence on the fancy than any other; and this influence they readily convey to those ideas, to which they are related, and which they resemble. I shall only infer from these practices, and this reasoning, that the effect of resemblance in enlivening the idea is very common; and as in every case a resemblance and a present impression must concur, we are abundantly supplied with experiments to prove the reality of the foregoing principle.
We may add force to these experiments by others of a different kind, in considering the effects of contiguity, as well as of resemblance. 'Tis certain, that distance diminishes the force of every idea, and that upon our approach to any object; tho' it does not discover itself to our senses; it operates upon the mind with an influence that imitates an immediate impression. The thinking on any object readily transports the mind to what is contiguous; but 'tis only the actual presence of an object, that transports it with a superior vivacity. When I am a few miles from home, whatever relates to it touches me more nearly than when I am two hundred leagues distant; tho' even at that distance the reflecting on any thing in the neighbourhood of my friends and family naturally produces an idea of them. But as in this latter case, both the objects of the mind are ideas; notwithstanding there is an easy transition betwixt them; that transition alone is not able to give a superior vivacity to any of the ideas, for want of some immediate impression1.
1. Naturane nobis, in quit, datum dicam, an errore quodam, ut, cum ea loca videamus, in quibus memoria dignos viros acceperimus multum esse versatos, magis moveamur, quam siquando eorum ipsorum aut facta audiamus, aut scriptum aliquod legamus? velut ego nunc moveor. Venit enim mihi Platonis in mentem: quem accipimus primum hic disputare solitum: Cujus etiam illi hortuli propinqui non memoriam solum mihi afferunt, sed ipsum videntur in conspectu meo hic ponere. Hic Speusippus, hic Xenocrates, hic ejus auditor Polemo; cujus ipsa illa sessio fuit, quam videamus. Equidem etiam curiam nostram, hostiliam dico, non hanc novam, quae mihi minor esse videtur post quam est major, solebam intuens Scipionem, Catonem, Laelium, nostrum vero in primis avum cogitare. Tanta vis admonitionis inest in locis; ut non sine causa ex his memoriae ducta sit disciplina. Cicero de Finibus, lib. 5.
"Should I," he said, "attribute to instinct or to some kind of illusion the fact that when we see those places in which we are told notable men spent much of their time, we are more powerfully affected than when we hear of the exploits of the men themselves or read something written? This is just what is happening to me now; for I am reminded of Plato who, we are told, was the first to make a practice of holding discussions here. Those gardens of his nearby do not merely put me in mind of him; they seem to set the man himself before my very eyes. Speusippus was here; so was Xenocrates; so was his pupil, Polemo, and that very seat which we may view was his.
"Then again, when I looked at our Senate-house (I mean the old building of Hostilius, not this new one; when it was enlarged, it diminished in my estimation), I used to think of Scipio, Cato, Laelius and in particular of my own grandfather.