conjoined with the other. After he has obferved feveral inftances of this nature, he then pronounces them to be connected. What alteration has happened to give rife to this new idea of connexion? Nothing but that he now feels these events to be connected in his imagination, and can readily foretel the existence of one from the appearance of the other. When we fay, therefore, that one object is connected with another, we mean only, that they have acquired a connexion in our thought, and give rife to this inference, by which they become proofs of each other's exiftence: A conclufion, which is fomewhat extraordinary; but which feems founded on fufficient evidence. Nor will its evidence be weakened by any general diffidence of the understanding, or fceptical fufpicion concerning every conclufion, which is new and extraordinary. No conclufions can be more agreeable to fcepticism than fuch as make difcoveries concerning the weakness and narrow limits of human reafon and capacity.

And what stronger inftance can be produced of the furprising ignorance and weakness of the understanding, than the prefent? For furely, if there be any relation among objects, which it imports us to know perfectly, it is caufe and effect. On this are founded all our reasonings concerning matter of fact or existence. By means of it alone we attain any affurance concerning objects, which are removed from the prefent teftimony of our memory and senses. The only immediate utility of all fciences, is to teach us, how to control and regulate future events by their caufes. Our thoughts and enquiries are, therefore, every moment, employed about this relation: Yet fo imperfect are the ideas which we form concerning it, that it is impoffible to give any just definition of caufe, except what is drawn from fomething extraneous and foreign to it. Similar

VOL. II.

G

objects

1

objects are always conjoined with fimilar. Of this we have experience. Suitably to this experience, therefore, we may define a cause to be an object, followed by another, and where all the objects, similar to the first, are followed by objects fimilar to the fecond. Or in other words, where, if the first object had not been, the fecond never had exifted. The appearance of a caufe always conveys the mind, by a cuftomary tranfition, to the idea of the effect. Of this alfo we have experience. We may, therefore, fuitably to this experience, form another definition of caufe; and call it, an object followed by another, and whofe appearance always conveys the thought to that other. But though both these definitions be drawn from circumstances foreign to the caufe, we cannot remedy this inconvenience, or attain any more perfect definition, which may point out that circumftance in the cause, which gives it a connexion with its effect. We have no idea of this connexion; nor even any distinct notion what it is we defire to know, when we endeavour at a conception of it. We fay, for inftance, that the vibration of this ftring is the cause of this particular found, But what do we mean by that affirmation? We either mean, that this vibration is followed by this found, and that all fimilar vibrations have been followed by fimilar founds: Or, that this vibration is followed by this found, and that upon the appearance of one, the mind anticipates the fenfes, and forms immediately an idea of the other. We may confider the relation of caufe and effect in either of these two lights; but beyond thefe, we have no idea of it*.

To recapitulate, therefore, the reafonings of this fection: Every idea is copied from fome preceding impreffion or fentiment; and where we cannot find any impreffion, we may be certain that there is no idea. In all fingle instances of

See NOTE [E].

the

the operation of bodies or minds, there is nothing that produces any impreffion, nor confequently can fuggeft any idea, of power or neceffary connexion. But when many uniform inftances appear, and the fame object is always followed by the fame event; we then begin to entertain the notion of caufe and connexion. We then feel a new fentiment or impreffion, to wit, a customary connexion in the thought or imagination between one object and its ufual attendant; and this fentiment is the original of that idea which we seek for. For as this idea arises from a number of similar instances, and not from any fingle instance; it muft arife from that circumstance, in which the number of inftances differ from every individual instance. But this cuftomary connexion or or transition of the imagination is the only circumftance, in which they differ. In every other particular they are alike. The first inftance which we faw of motion, communicated by the fhock of two billiard-balls (to return to this obvious illustration) is exactly fi milar to any inftance that may, at prefent, occur to us; except only, that we could not, at firft, infer one event from the other; which we are enabled to do at prefent, after fo long a course of uniform experience. I know not, whether the reader will readily apprehend this reafoning. I am afraid, that, fhould I multiply words about it, or throw it into a greater variety of lights, it would only become more obfcure and intricate. In all abftract reasonings, there is one point of view, which, if we can happily hit, we fhall go farther towards illuftrating the fubject, than by all the eloquence and copious expreffion in the world. This point of view we fhould endeavour to reach, and referve the flowers of rhetoric for fubjects which are more adapted to them. G 2

[85]

IT

SECTION VIII.

Of LIBERTY and NECESSITY.

PARTI.

might reasonably be expected, in queftions, which have been canvaffed and difputed with great eagerness, fince the first origin of science and philofophy, that the meaning of all the terms, at least, should have been agreed upon among the difputants; and our enquiries, in the courfe of two thousand years, been able to pafs from words to the true and real fubject of the controverfy. For how eafy may it seem to give exact definitions of the terms employed in reafoning, and make these definitions, not the mere found of words, the object of future fcrutiny and examination? But if we confider the matter more narrowly, we shall be apt to draw a quite oppofite conclufion. From this circumstance alone, that a controversy has been long kept on foot, and remains ftill undecided, we may prefume, that there is fome ambiguity in the expreffion, and that the difputants affix different ideas to the terms employed in the controverfy. For as the faculties of the mind are supposed to be naturally alike in every individual; otherwife nothing could be more fruitless than to reafon or difpute together; it were impof

fible,