SECT. 111.

The fame Subject-Cuftom, an affociating Principle.

T was hinted, and fome of the preceding examples imply, that Cuftom is a principle of Affociation. Its influence is powerful and extenfive. Two objects, or ideas, that are not fimilar, nor contrary, nor contiguous, nor related as caufe and effect, or in any other way, may, by appearing once or twice in the fame groupe, acquire an affinity no lefs intimate with refpect to the Imagination, than if art or nature had combined them in one permanent affemblage; and the one fhall fuggeft the other to the mind as readily as the idea of a door or window fuggefts that of a houfe. You may have heard one of the common people, in order to amuse his companions who were not in the fecret, offer to lay a wager, that they should never pare their nails on Monday without thinking of the fox. What connection, one would fay, is there between the nails, or the act of paring them on the fecond day of the week, and that animal? Truly none. But when you are once led to take notice of these ideas thus affociated, you may afterwards find, they will fo adhere, as that, if you attend to the one, the other will immediately prefent itself.

Many

Many of our actions do in this way suggest certain thoughts, from no other difcernible caufe, but that their union, which at firft was accidental, having been once and again repeated or renewed, or once accompanied with fome ftriking circumftance, has fettled into a permanent Affociation. If, for example, while I am performing a certain piece of mufick, or while I am making a vifit at the houfe of a friend, I fhould receive fome very agreeable, or very difagreeable, intelligence, it is not unlikely, that the fame mufick, or a repetition of the vifit, will afterwards put me in mind of that intelligence, or at leaft convey fome vague idea of good or of bad fortune. Or if, in my walks, I should, for feveral days, meet unexpectedly, in one place, with one and the fame perfon, diftinguifhed by fuch qualities, good or bad, as would make me attend to him, it would not be wondered at, if the ideas of that place and perfon should ever after mutually fuggeft each other to my mind. In these cafes Contiguity would co-operate with Custom in establishing the Affociation; which would probably be ftronger or weaker, in proportion as the coincidence of the objects was accompanied, more or lefs, with furprise, joy, forrow, or any other painful or pleasurable emotion,

Whence comes it, that, on hearing the founds, or feeing the characters, of a known language, the mind makes fo quick a tranfition to the thing fignified, that it feems to overlook the impreffion made on the eye or ear, and to attend to the meaning only? Is it not, because the articulate found, or the written character, has long been affociated with the idea fignified, and has 13 formed

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formed in the mind a habit of paffing inftantaneoufly from the one to the other? In like man. ner, and for the fame reason, the thoughts, that occur to us, do inftantly fuggeft the words, by which they are wont to be expreffed; and that whether we write, or fpeak, or only meditate. For although words and thoughts are different things (as appears from this, that deaf men think, who know nothing of words) yet words are, as it were, the drefs, or the guife, in which our thoughts prefent themselves; fo that we cannot revolve ideas in our minds, without revolving words at the fame time; even as we cannot think of the character of an absent friend, without recollecting his vifible appearance.

Men, who were born deaf, and have never been taught to read, do probably, in attending to their thoughts, especially to their abstract notions, revolve thofe vifible figns by which they are accustomed to exprefs them. If, for example, it be their way to fignify good, by holding up their thumb, and evil, by ftretching out the little finger, it is, I think, probable, that, in their minds, the ideas of Good and Evil will be accompanied with thofe of the thumb and little finger thefe organs being as really their figns for thofe ideas, as the words good and evil are ours. If they have acquired the ready use of written language, it is reasonable to fuppofe, that they will affociate their abftract notions with the vifible appearance of the correfponding words, as printed or written. But this is only conjecture. For I have never had any conversation upon this fubject with men born deaf; and I believe it would not be eafy to make them compre

hend

hend the questions that might lead to the illuftration of it.

In nothing do we make a more rapid tranfition from the fign to the thing fignified, than in judging of the diftance, magnitude, and figure, of things, from their vifible appearance. The eye perceives only light and colour: yet by the eye we estimate figure, and magnitude, and confequently distance; because we have been always accustomed to take certain arrangements of colour and light for the figns of thofe tangible qualities. And this estimation is fo inftantaneous, that we think we see the magnitude, the figure, and the distance, when in fact we only fee colours and light variously difpofed. Thus we in fome meafure mistake a judgment for a fenfation; and are led by the fign to the thing fignified, almost without being confcious that we perceive the sign at all. The Affociation here is as ftrong, as between words and ideas; but it begins to be formed at an earlier period. It begins, as foon as we can use our hands for the purpose of perception; and is compleated long before we are capable of rational inquiry *,

Muficians exprefs their notes, and the masters of dancing their motions and attitudes, by figns

or

This difcourfe was addreffed at firft to those who were fuppofed to be acquainted with opticks. To make the paffage intelligible to fome readers, the following illuftration may be neceffary.

1. By Distance I here mean, the space between us and other things. Blind men perceive, and can measure it, by Touch: that is, by stretching out their hand, or walking forward, till they come in contact with the distant object. And, from

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or fymbols delineated on paper; in the use of which, as in reading and writing, their minds instantly pass from the view of the fign to that meaning which cuftom has annexed to it: and, if

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the inftance of a young man, who had been born blind, and who was made to fee at the age of fourteen (his cataracts being then couched by the famous Cheffelden) it appears, Sight alone, unaided by touch, would not make diftance perceptible. This boy, when he first opened his eyes, perceived light and colour, which however seemed to touch the organ of fight; and it was by ftretching out his hand, or walking up to the coloured object, that he found out its diftance: the very way in which he was wont to eftimate distance, while he was blind. Afterwards, obferving, that certain changes in the visible appearance of bodies do always accompany a change of distance, he fell upon a method of eftimating the distance by the visible appearance: and his method was the fame with ours. For, while a body retires from the eye, its visible appearance becomes fmaller, its colours lefs lively, and its outlines lefs diftin&t; and a number of intermediate objects, more or fewer according to the distance, appears between us and it. And hence, a certain vifible appearance comes to be the fign of a certain diftance. And if a painter can imitate this vifible appearance, the objects he draws in an artificial landscape will feem to be, fome of them near, and others remote, though all are really at the fame distance from the eye. Thofe that are to feem near muft be vivid in colour, large in fize, diftinct in outline, and feparated from the eye of the fpectator by few or no intermediate objects: thofe that are intended to appear as if they were more remote, must be smaller in fize, more faint in colour, and in outline more indistinct, and must seem to be feparated from the fpectator by a greater number of intermediate objects.

The heavenly bodies are always feen at the fame apparent distance and therefore we know not what change in their vifible appearance a change of diftance might occafion. To afcertain their diftance by touch, is impoffible; and between them and us there are no intermediate objects of known magnitude, to enable us to judge of it. Hence to the eye they all feem to be indefinitely, and equally, diftant; and, being fcattered over the whole fky, made every part of it feem indefinitely, and equally, diftant; and, confequently, give to the whole fky the appearance of part of the