other beings may poffefs many fenfes, of which we can have no conception; because the ideas of them have never been introduced to us, in the only manner, by which an idea can have access to the mind, to wit, by the actual feeling and fenfation.

There is, however, one contradictory phænomenon, which may prove, that it is not abfolutely impoffible for ideas to arife, independent of their correfpondent impreffions. I believe it will readily be allowed, that the feveral diftinct ideas of colour, which enter by the eye, or those of found, which are conveyed by the ear, are really different from each other; though, at the fame time, refembling. Now if this be true of different colours, it must be no lefs fo of the different shades of the fame colour; and each fhade produces a diftinct idea, independent of the reft. For if this fhould be denied, it is poffible, by the continual gradation of fhades, to run a colour infenfibly into what is most remote from it; and if you will not allow any of the means to be different, you cannot, without abfurdity, deny the extremes to be the fame. Suppose, therefore, a perfon to have enjoyed his fight for thirty years, and to have become perfectly well acquainted with colours of all kinds, except one particular shade of blue, for instance, which it never has been his fortune to meet with. Let all the different fhades of that colour, except that fingle one, be placed before him, defcending gradually from the deepest to the lighteft; it is plain, that he will perceive a blank, where that shade is wanting, and will be fenfible, that there is a greater diftance in that place between the contiguous colours than in any other. Now I afk, whether it be poffible for him, from his own imagination, to supply this deficiency, and raise up to himself the idea of that

particular fhade, though it had never been conveyed to him by his fenfes? I believe there are few but will be of opinion that he can: And this may ferve as a proof, that the fimple ideas are not always, in every inftance, derived from the correfpondent impreffions; though this inftance is fo fingular, that it is fcarcely worth our obferving, and does not merit, that for it alone we should alter our general maxim.

Here, therefore, is a propofition, which not only feems, in itself, fimple and intelligible; but, if a proper ufe were made of it, might render every difpute equally intelligible, and banish all that jargon, which has fo long taken poffeffion of metaphyfical reasonings, and drawn fuch difgrace upon them. All ideas, especially abftract ones, are naturally faint and obfcure: The mind has but a flender hold of them: They are apt to be confounded with other refembling ideas; and when we have often employed any term, though without a diftin&t meaning, we are apt to imagine it has a determinate idea, annnexed to it. On the contrary, all impreffions, that is, all fenfations, either outward or inward, are strong and vivid: The limits between them are more exactly determined: Nor is it easy to fall into any error or mistake with regard to them. When we entertain, therefore, any fufpicion, that a philofophical term is employed without any meaning or idea (as is but too frequent) we need but enquire, from what impreffion is that fuppofed idea derived? And if it be impoffible to affign any, this will ferve to confirm our fufpicion. By bringing ideas into fo clear a light, we may reasonably hope to remove all difpute, which may arife, concerning their nature and reality *.

* See NOTE [A].

It

SECTION III.

Of the AssoCIATION of IDEAS.

T is evident, that there is a principle of connexion between the different thoughts or ideas of the mind, and that, in their appearance to the memory or imagination, they introduce each other with a certain degree of method and regularity. In our more serious thinking or difcourfe, this is fo obfervable, that any particular thought, which breaks in upon this regular tract or chain of ideas, is immediately remarked and rejected. And even in our wildest and most wandering reveries, nay in our very dreams, we fhall find, if we reflect, that the imagination ran not altogether at adventures, but that there was still a connexion upheld among the different ideas, which fucceeded each other. Were the loofeft and freeft converfation to be tranfcribed, there would immediately be obferved fomething, which connected it in all its tranfitions. Or where this is wanting, the perfon, who broke the thread of difcourfe, might still inform you, that there had fecretly revolved in his mind a fucceffion of thought, which had gradually led him away from the fubject of converfation. Among different languages, even where we cannot fufpect the least connexion or communication, it is found, that the words, expreffive of ideas, the most compounded, do yet nearly

C 4

"nearly correfpond to each other: A certain proof, that the fimple ideas, comprehended in the compound ones, were bound together by fome univerfal principle, which had an equal influence on all mankind.

Though it be too obvious to escape obfervation, that different ideas are connected together; I do not find, that any philofopher has attempted to enumerate or clafs all the principles of affociation; a fubject, however, that feems worthy of curiofity. To me, there appear to be only three principles of connexion among ideas, namely, Refemblance, Contiguity in time or place, and Caufe or Effect.

That these principles ferve to connect ideas will not, I believe, be much doubted. A picture naturally leads our thoughts to the original*: The mention of one apartment in a building naturally introduces an enquiry or difcourfe concerning the others + And if we think of a wound, we can fcarcely forbear reflecting on the pain which follows it. But that this enumeration is compleat, and that there are no other principles of affociation, except thefe, may be difficult to prove to the fatisfaction of the reader, or even to a man's own fatisfaction. All we can do, in such cases, is to run over feveral inftances, and examine carefully the principle, which binds the different thoughts to each other, never stopping till we render the principle as general as poffible. The more inftances we examine, and the more care we employ, the more affurance fhall we acquire, that the enumeration, which we form from the whole, is compleat and entire. Instead of entering into a detail of this kind, which would lead into many ufelefs fubtilties, we

Refemblance.

† Contiguity.

Caufe and Effect,

fhall

fhall confider fome of the effects of this connexion upon the paffions and imagination; where we may open a field of speculation more entertaining, and perhaps more inftructive, than the other.

As a man is a reasonable being, and is continually in pursuit of happiness, which he hopes to attain by the gratification of fome paffion or affection, he seldom acts or fpeaks or thinks without a purpose and intention.es He has still some object in view; and however improper the means may fometimes be, which he chufes for the attainment of his end, he never lofes view of an end; nor will he fo much as throw away his thoughts or reflections, where he hopes not to reap fome fatisfaction from them.

In all compofitions of genius, therefore, it is requifite, that the writer have fome plan or object; and though he may be hurried from this plan by the vehemence of thought, as in an ode, or drop it carelessly, as in an epiftle or effay, there must appear some aim or intention, in his first setting out, if not in the compofition of the whole work. A production without a defign would resemble more the ravings of a madman, than the fober efforts of genius and learning.

As this rule admits of no exception, it follows, that, in narrative compofitions, the events or actions, which the writer relates, must be connected together, by some bond or tye: They must be related to each other in the imagination, and form a kind of Unity, which may bring them under one plan or view, and which may be the object or end of the writer in his first undertaking.

This connecting principle among the feveral events, which form the fubject of a poem or hiftory, may be very different, according to the different defigns of the

poet