tion is fufficiently copious, and carried on according to the rules of art, it forces conviction no less than demonstration itself does. The greatest part of human knowledge refts upon evidence of this kind. Indeed we can have no other for general truths which are contingent in their nature, and depend upon the will and ordination of the maker of the world. He governs the world he has made, by general laws. The effects of these laws in particular phenomena are open to our obfervation; and by observing a train of uniform effects with due caution, we may at laft decypher the law of nature by which they are regulated.

Lord Bacon has difplayed no less force of genius in reducing to rules this method of reasoning, than Aristotle did in the method of fyllogifin. His Novum Organum ought therefore to be held as a most important addition to the ancient logic. Those who understand it, and enter into the spirit of it, will be able to distinguish the chaff from the wheat in philofophical difquifitions into the works of God. They will learn to hold in due contempt all hypotheses and theories, the creatures of human imagination, and to refpect nothing but facts fufficiently vouched, or conclufions drawn from them by a fair and chaste interpretation of nature.

Most arts have been reduced to rules, after they had been brought to a confiderable degree of perfection by the natural fagacity of artifts; and the rules have been drawn from the best examples of the art that had been before exhibited: but the art of philofophical induction was delineated by Lord Bacon in a very ample manner, before the world had feen any tolerable example of it. This, altho' it adds greatly to the merit of the author, must have produced fome obfcurity in the work, and a defect of proper examples for illuftration. This defect may now be eafily fupplied, from thofe authors who, in their philofophical difquifitions, have most strictly pursued the path pointed out in the Novum Organum. Among thefe Sir Ifaac Newton feems to hold the firft rank, having,

in

in the third book of his Principia, and in his Optics, had the rules of the Novum Organum conftantly in his eye.

I think Lord Bacon was also the first who endeavoured to reduce to a fyftem the prejudices or biaffes of the mind, which are the caufes of falfe judgement, and which he calls the idols of the human understanding. Some late writers of logic have very properly introduced this into their fyftem; but it deferves to be more copiously handled, and to be illustrated by real examples.

It is of great confequence to accurate reasoning, to distinguish first principles which are to be taken for granted, from propofitions which require proof. All the real knowledge of mankind may be divided into two parts: the first confifting of felf-evident propofitions; the fecond, of those which are deduced by just reafoning from felf-evident propofitions. The line which divides these two parts ought to be marked as diftinctly as poffible, and the principles that are self-evident reduced, as far as can be done, to general axioms. This has been done in mathematics from the beginning, and has tended greatly to the emolument of that fcience. It has lately been done in natural philosophy: and by this means that fcience has advanced more in an hundred and fifty years, than it had done before in two thousand. Every science is in an unformed state until its first principles are afcertained: after that is done, it advances regularly, and fecures the ground it has gained.

Altho' first principles do not admit of direct proof, yet there must be certain marks and characters, by which thofe that are truly fuch may be distinguished from counterfeits. These marks ought to be defcribed, and applied, to diftinguish the genuine from the fpurious.

In the ancient philofophy there is a redundance, rather than a defect, of first principles. Many things were affumed under that character without a juft title: That nature abhors a vacuum ;

That

That bodies do not gravitate in their proper place; 'That the heavenly bodies undergo no change; That they move in perfect circles, and with an equable motion. Such principles as these were affumed in the Peripatetic philofophy, without proof, as if they were felf-evident.

Des Cartes, fenfible of this weakness in the ancient philofophy, and defirous to guard against it in his own fyftem, refolved to admit nothing until his affent was forced by irresistible evidence. The first thing which he found to be certain and evident was, that he thought, and reasoned, and doubted. He found himself under a neceffity of believing the existence of thofe operations of mind of which he was confcious: and having thus found fure footing in this one principle of consciousness, he rested satisfied with it, hoping to be able to build the whole fabric of his knowledge upon it; like Archimedes, who wanted but one fixed point to move the whole earth. But the foundation was too narrow; and in his progress he unawares affumes many things lefs evident than those which he attempts to prove. Altho' he was not able to suspect the testimony of consciousness, yet he thought the te ftimony of sense, of memory, and of every other faculty, might be fufpected, and ought not to be received until proof was brought that they are not fallacious. Therefore he applies these faculties, whose character is yet in queftion, to prove, That there is an infinitely perfect Being, who made him, and who made his fenfes, his memory, his reafon, and all his faculties; That this Being is no deceiver, and therefore could not give him faculties that are fallacious; and that on this account they deserve credit.

It is ftrange, that this philofopher, who found himfelf under a neceffity of yielding to the teftimony of confcioufnefs, did not find the fame neceflity of yielding to the teftimony of his fenfes, his memory, and his understanding: and that while he was certain that he doubted, and reafoned, he was uncertain whether two

and

and three made five, and whether he was dreaming or awake. It is more strange, that fo acute a reafoner fhould not perceive, that his whole train of reafoning to prove that his faculties were not fallacious, was mere fophiftry: for if his faculties were fallacious, they might deceive him in this train of reasoning; and fo the conclufion, That they were not fallacious, was only the testimony of his faculties in their own favour, and might be a fallacy.

It is difficult to give any reafon for distrusting our other faculties, that will not reach consciousness itself. And he who distrusts those faculties of judging and reafoning which God hath given him, must even reft in his fcepticism till he come to a found mind, or until God give him new faculties to fit in judgement upon the old. If it be not a first principle, That our faculties are not fallacious, we must be abfolute fceptics: for this principle is incapable of proof; and if it is not certain, nothing else can be certain.

Since the time of Des Cartes, it has been fashionable with those who dealt in abstract philosophy, to employ their invention in finding philofophical arguments, either to prove those truths which ought to be received as first principles, or to overturn them and it is not easy to fay, whether the authority of first principles is more hurt by the first of these attempts, or by the laft; for fuch principles can stand fecure only upon their own bottom; and to place them upon any other foundation than that of their intrinfic evidence, is in effect to overturn them.

I have lately met with a very fenfible and judicious treatise, wrote by Father Buffier about fifty years ago, concerning first principles, and the fource of human judgements, which, with great propriety, he prefixed to his treatise of logic. And indeed I apprehend it is a subject of such confequence, that if inquisitive

men

men can be brought to the fame unanimity in the first principles of the other sciences, as in those of mathematics and natural philofophy, (and why should we despair of a general agreement in things that are self-evident?), this might be confidered as a third grand æra in the progrefs of human reafon.