reflecting upon its own operations. Therefore to make logic the firft branch of science that is to be taught, is an old error that ought to be corrected.

SECT. 2. Of the Improvement of Logic.

In compofitions of human thought expreffed by fpeech or by writing, whatever is excellent and whatever is faulty, fall within the province, either of grammar, or of rhetoric, or of logic. Propriety of expreffion is the province of grammar; grace, elegance, and force, in thought and in expreffion, are the province of rhetoric; justness and accuracy of thought are the province of logic.

The faults in compofition, therefore, which fall under the cen→ fure of logic, are obfcure and indiftinct conceptions, falfe judgement, inconclufive reafoning, and all improprieties in diftinctions, definitions, divifion, or method. To aid our rational powers, in avoiding these faults and in attaining the oppofite excellencies, is the end of logic; and whatever there is in it that has no tendency to promote this end, ought to be thrown

out.

The rules of logic being of a very abstract nature, ought to be illuftrated by a variety of real and ftriking examples taken from the writings of good authors. It is both instructive and entertaining, to observe the virtues of accurate compofition in writers of fame. We cannot fee them, without being drawn to the imitation of them, in a more powerful manner than we can be by dry rules. Nor are the faults of fuch writers lefs inftructive or lefs powerful monitors. A wreck, left upon a fhoal, or upon a rock, is not more useful to the failor, than the faults of good writers, when fet up to view, are to thofe who come after them. It was a

happy thought in a late ingenious writer of English grammar, to collect under the feveral rules, examples of bad English found in the most approved authors. It were to be wifhed that the rules of logic were illustrated in the fame manner. By this means, a fyftem of logic would become a repofitory; wherein whatever is moft acute in judging and in reasoning,, whatever is most accurate in dividing, distinguishing, and defining, should be laid up and difpofed in order for our imitation; and wherein the falfe fleps of eminent authors should be recorded for our admonition.

After men had laboured in the fearch of truth near two thoufand years, by the help of fyllogifms, Lord Bacon propofed the method of induction, as a more effectual engine for that purpose. His Novum Organum gave a new turn to the thoughts and labours of the inquifitive, more remarkable, and more useful, than that which the Organum of Ariftotle had given before; and may be confidered as a fecond grand æra in the progrefs of human reafon.

The art of fyllogifm produced numberlefs difputes, and numberlefs fects, who fought against each other with much animofity, without gaining or lofing ground; but did nothing confiderable for the benefit of human life. The art of induction, firft delineated by Lord Bacon, produced numberless laboratories and obfervatories, in which Nature has been put to the question by thoufands of experiments, and forced to confefs many of her fecrets, which before were hid from mortals. And by thefe, arts have been improved, and human knowledge wonderfully increased.

In reafoning by fyllogifm, from general principles we defcend to a conclufion virtually contained in them. The procefs of induction is more arduous; being an afcent from particular premifes to a general conclufion. The evidence of fuch general conclufions is not demonftrative, but probable; but when the induc

tion

tion is fufficiently copious, and carried on according to the rules of art, it forces conviction no lefs 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 thefe laws in particular phenomena are open to our obfervation; and by obferving 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 displayed 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 hypothefes and theories, the creatures of human imagination, and to respect nothing but facts fufficiently vouched, or conclufions drawn from them by a fair and chafte 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 beft 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 easily supplied, from those authors who, in their philofophical difquifitions, have most strictly purfued 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 alfo the first who endeavoured to reduce to a system the prejudices or biaffes of the mind, which are the caufes of false judgement, and which he calls the idols of the human underflanding. Some late writers of logic have very properly introduced this into their system; 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 confisting of self-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 felf-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 thoufand. Every science is in an unformed state until its first principles are ascertained: after that is done, it advances regularly, and fecures the ground it has gained.

Altho' firft principles do not admit of direct proof, yet there must be certain marks and characters, by which thofe that are truly such may be distinguished from counterfeits. These marks ought to be described, 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 irrefiftible evidence. The first thing which he found to be certain and evident was, that he thought, and reafoned, 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 confcioufnefs, he refted fatisfied 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 progrefs he unawares affumes many things lefs evident than thofe which he attempts to prove. Altho' he was not able to fufpect the testimony of consciousness, yet he thought the teftimony of fenfe, 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 thefe faculties, whofe character is yet in question, 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 deferve credit.

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

and