difcovered in a fubject, where, at firft view, and from an abstract confideration, we fhould leaft expect to find it.

'Tis evident, that HOMER, in the course of his narration, exceeds the first propofition of his fubject; and that the anger of ACHILLES, which caufed the death of HECTOR, is not the fame with that which produced fo many ills to the GREEKS. But the ftrong connexion between these two movements, the quick tranfition from one to another, the contraft † between the effects of concord and difcord among the princes, and the natural curiofity which we have to fee ACHILLES in action, after fuch long repofe; all these causes carry on the reader, and produce a fufficient unity in the subject.

It may be objected to MILTON, that he has traced up his causes to too great a distance, and that the rebellion of the angels produces the fall of man by a train of events, which is both very long and very cafual. Not to mention that the creation of the world, which he has related at length, is no more the cause of that catastrophe, than of the battle of PHARSALIA, or any other event, that has ever happened. But if we confider, on the other hand, that all these events, the rebellion of the angels, the creation of the world, and the fall of man, resemble each other, in being miraculous and out of the common course of nature; that they are fuppofed to be contiguous in time; and that being detached from all other events, and being the only original facts, which revelation difcovers, they ftrike the eye at once, and naturally recall each other to the thought or imagination: If we confider all these circumftances, I fay, we fhall find, that thefe parts of the action have a fufficient unity to make them be compre

+ Contraft or contrariety is a connexion among ideas, which may, per. haps, be confidered as a mixture of caufation and refemblance. Where two objects are contrary, the one deftroys the other, i. e. is the caufe of its annihilation, and the idea of the annihilation of an object implies the idea of its former exiftence.

hended

To which we may

hended in one fable or narration. add, that the rebellion of the angels and the fall of man have a peculiar resemblance, as being counterparts to each other, and presenting to the reader the fame moral, of obedience to our Creator.

These loose hints I have thrown together, in order to excite the curiofity of philofophers, and beget a suspicion at least, if not a full persuasion, that this subject is very copious, and that many operations of the human mind depend on the connexion or affociation of ideas, which is here explained. Particularly, the fympathy between the paffions and imagination will, perhaps, appear remarkable; while we obferve that the affections, excited by one object, pass easily to another connected with it; but transfuse themselves with difficulty, or not at all, along different objects, which have no manner of connexion together. By introducing, into any compofition, perfonages and actions, foreign to each other, an injudicious author loses that communication of emotions, by which alone he can intereft the heart, and raise the paffions to their proper height and period. The full explication of this principle and all its confequences would lead us into reasonings too profound and too copious for this enquiry. 'Tis fufficient, at present, to have established this conclufion, that the three connecting principles of all ideas are the relations of Refemblance, Contiguity, and Caufation.

SECTION

SECTION IV.

SCEPTICAL DOUBTS concerning the OPERATIONS of the UNDERSTANDING.

A

PART I.

LL the objects of human reason or enquiry may naturally be divided into two kinds, viz. Relations of Ideas and Matters of Fact. Of the firft kind are the sciences of Geometry, Algebra, and Arithmetic; and in fhort, every affirmation, which is either intuitively or demonftratively certain. That the fquare of the hypothenuse is equal to the fquare of the two fides, is a propofition, which expreffes a relation between these figures. That three times five is equal to the half of thirty, expreffes a relation between these numbers. Propofitions of this kind are difcoverable by the mere operation of thought, without dependence on what is any where exiftent in the universe. Tho' there never were a circle or triangle in nature, the truths demonftrated by EUCLID, would for ever retain their certainty and evidence.

Matters of fact, which are the second objects of human reason, are not ascertained in the fame manner; nor is our evidence of their truth, however great, of a like nature with the foregoing. The contrary of every matter of fact is ftill poffible; because it can never imply a contradiction, and is conceived by the mind with equal faVOL. II.

D

cility

cility and diftinctnefs, as if ever so conformable to reality. That the fun will not rife to-morrow is no lefs intelligible a propofition, and implies no more contradiction, than the affirmation, that it will rife. We should in vain, therefore, attempt to demonftrate its falfhood. Were it demonstratively false, it would imply a contradiction, and could never be diftinctly conceived by the mind.

It may, therefore, be a fubject worthy curiofity, to enquire what is the nature of that evidence, which assures us of any real existence and matter of fact, beyond the present teftimony of our fenfes, or the records of our memory. This part of philosophy, 'tis obfervable, has been little cultivated, either by the ancients or moderns; and therefore our doubts and errors, in the profecution of so important an enquiry, may be the more excufable, while we march thro' fuch difficult paths, without any guide or direction. They may even prove useful, by exciting curiofity, and deftroying that implicit faith and fecurity, which is the bane of all reafoning and free enquiry. The. discovery of defects in the common philofophy, if any fuch there be, will not, I prefume, be a discouragement, but rather an incitement, as is ufual, to attempt fomething more full and fatisfactory, than has yet been proposed to the public.

All reafonings concerning matter of fact feem to be founded in the relation of Cause and Effect. By means of that relation alone we can go beyond the evidence of our memory and fenfes. If you were to ask a man, why he believes any matter of fact, which is abfent; for inftance, that his friend is in the country, or in FRANCE; he would give you a reafon; and this reason would be fome other fact; as a letter received from him, or the knowledge of his former refolutions and promises. A man, finding a watch or any other machine in a defart island, would conclude, that there had once been men in

that

that ifland. All our reasonings concerning fact are of the fame nature. And here 'tis conftantly fuppofed, that there is a connexion between the prefent fact and that inferred from it. Were there nothing to bind them to gether, the inference would be entirely precarious. The hearing of an articulate voice and rational difcourfe in the dark affures us of the prefence of fome perfon: Why? because these are the effects of the human make and fa bric, and closely connected with it. If we anatomize all the other reasonings of this nature, we fhall find, that they are founded in the relation of cause and effect, and that this relation is either near or remote, direct or collateral. Heat and light are collateral effects of fire, and the one effect may justly be inferred from the other.

If we would fatisfy ourselves, therefore, concerning the nature of that evidence, which affures us of all matters of fact, we must enquire how we arrive at the knowlege of caufe and effect.

I fhall venture to affirm, as a general propofition, which admits of no exception, that the knowlege of this relation is not, in any inftance, attained by reasonings à priori; but arifes entirely from experience, when we find, that any particular objects are conftantly conjoined with each other. Let an object be prefented to a man of ever so strong natural reafon and abilities; if that object be entirely new to him, he will not be able, by the most accurate examination of its fenfible qualities, to difcover any of its caufes or effects. ADAM, tho' his rational faculties be fuppofed, at the very firft, entirely perfect, could not have inferred from the fluidity and transparency of water, that it would fuffocate him, or from the light and warmth of fire, that it would confume him. No object ever discovers, by the qualities which appear to the fenfes, either the caufes, which produced it, or the effects, which will arife from it; nor can our reason,

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