and as thofe of geometry actually are; and therefore, however neceffary it may be to admit the phyfical axiom of the u niverfality and the neceffity of a Caufe for every Event or fuppofed Effect, it must be equally, and even previously, neceffary to have it rendered clear and precife; which can be done only by a particular explanation, and full illuftration of the notion expreffed by the term Cause, and of the relation conceived to fubfift between Cause and Effect..

It is in vain, and would be almost abfurd, to attempt to fettle that preliminary point, by giving any arbitrary definitions, however clear and precife thefe might be made, of the notions and of the terms in queftion. Such definitions may easily be given, and many different definitions of them have been given accordingly, both in ancient and modern times. All of these definitions of any one term or notion, fuch as Caufe, may be bad; that is, either altogether erroneous; or defective, and confequently too general; or redundant, and confequently too limited and partial, in

their

their application: nay, all but one of them must be bad, forafmuch as they are different.

It would require a differtation much longer than I should wish this Introduction to be, to explain the laws of definition, with respect to natural objects, and to thofe notions that are univerfal among mankind, and are the natural and spontaneous fuggeftions of the human faculties, and which may fairly be regarded as fundamental and indefeasible laws in the conftitution of the Human Mind.

It would even require a difcuffion inconveniently and difproportionately long for this place, to point out all the improprieties, and all the pernicious confequences, which have indeed been very extenfive and very permanent, of the arbitrary definitions and erroneous doctrines concerning caufes, that make a fundamental part of the Platonic and Ariflotelian philofophy. Thefe perhaps are more ancient even than PLATO, and may have only been borrowed by him from fome of his predeceffors;

deceffors; but they were fully adopted, and in fome measure altered and modified, by his fcholar ARISTOTLE; and by him were established, as the very bafis of science, for more than two thousand years. The whole of that boasted doctrine, impartially confidered, may fairly be refolved into one vague, confufed, unnatural notion, (ro it iv), which fome philofopher, in an evil hour for fcience, had unluckily formed for himself, and contrived to exprefs by an arbitrary and bad definition of the Greek term air, which we tranflate Caufe. I call the definition and use of that term, by PLATO, and ARISTOTLE, and their followers, arbitrary and bad, not merely because it is too vague and general, comprehending, for example, the matter, and the form, as well those things usually called and thought causes, and fo is a violation of propriety of language, in Greek, as well as in Latin, and in the modern languages; but much more because it is an attempt to do violence to the laws of human thought, and to make us confider several things as fpecies of one genus, among which things there is not in

reality a generic nature. It is an attempt to make a falfe and unnatural genus, which is indeed impracticable; but if it were poffible, it would be a mortal fin in the philofophy as well as in the history of nature it would be almost as bad as a falfe axiom. It is difficult to exprefs in common language the nature of the violence done, or rather attempted, to the indefeasible laws of human thought, by ARISTOTLE'S doctrine of Caufes: the nearest that I can come to a just expreffion of it, is by obferving, that it is a fort of counterpart to an arbitrary and unnatural divifion of a fubject of thought. On fuch an improper, or, as he calls it, inelegant divifion, CICERO has very fhrewdly remarked, Hoc non eft DIVIDERE, fed FRANGERE rem: of ARISTOTLE's doctrine of Caufes, we may fay, with equal truth, though not with equal wit, Hoc non eft COMPREHENDERE, fed CONFUNDERE res.-But as the minute difcuffion of that doctrine will come in more properly afterwards in the profecution of thefe Eflays, and is not immediately neceffary for the understanding of any thing contained in this volume, I poftpone

poftpone it for the prefent; only observing, in the words of BACON, Ut aqua nor afcendet altius quam caput fontis a quo promanat, ita doctrina ab ARISTOTELE deducta fupra doctrinam ARISTOTELIS nunquam affurget.

With refpect to the other point, the exact import and extent of the common and natural notion of the relation of caufe and effect, concerning which relation I conceive that various fanciful and erroneous opinions have been entertained, and of which notion many arbitrary and confufed and false definitions have been given, I think it a most important and interesting inquiry.

It is by no means neceffary to examine minutely the various fpeculations and definitions of different philofophers about it; for that would be only to learn the opinions of a few individuals concerning a matter of fact, the truth of which is quite independent of them and their fpeculations, and may be completely afcertained without the smallest reference to