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powerful manner than we can be by dry rules. Nor are the faults of fuch writers, lefs instructive 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 those 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 moft approved authors. It were to be wifhed that the rules of logic were illuftrated in the fame manner. By these means, a fyftem of logic would become a repofitory; wherein whatever is moft acute in judging and in reafoning, whatever is most accurate in dividing, diftinguishing, and defining, fhould be laid up and difpofed in order for our imitation; and wherein the falfe fteps of eminent authors fhould be recorded for our admonition.

After men had laboured in the fearch of truth near two thousand 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 progress of human reason.

The art of fyllogifm produced numberless dif putes; and numberless fects who fought against

each

each other with much animofity, without gaining or lofing ground, but did nothing confiderable for the benefit of human life. The art of induction, first delineated by Lord Bacon, produced numberlefs laboratories and obfervatories; in which Nature has been put to the queftion by thoufands of experiments, and forced to confefs many of her fecrets, that before were hid from mortals. And by these, 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 process of induction is more arduous; being an afcent from particular premises to a general conclufion. The evidence of fuch general conclufions is probable only, not demonftrative but when the induction is fufficiently copious, and carried on according to the rules of art, it forces conviction no lefs than demonftration itfelf 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. effects of these laws in particular phenomena, are open to our obfervation; and by obferving a train of uniform effects with due caution, we may at laft

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Lord Bacon has difplayed no less force of genius in reducing to rules this method of reasoning, than Aristotle did in the method of fyllogifm. His Novum Organum ought therefore to be held as a most important addition to the ancient logic. Those who understand it, and enter into its fpirit will be able to diftinguish 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 seen any tolerable example of it. This, although it adds greatly to the merit of the author, muft 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 the most strictly purfued the path pointed out in the Novum Organum. Among these Sir Ifaac Newton

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VOL. III.

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Newton appears to hold the firft rank; having, 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 causes of false judgments and which he calls the idols of the bu-' man understanding. Some late writers of logic have very properly introduced this into their fyftem; but it deserves to be more copiously handled, and to be illuftrated by real examples.

It is of great confequence to accurate reasoning, to distinguish firft 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 firft confifting of felf-evident propofitions; the fecond, of those which are deduced by juft reasoning from felf-evident propofitions. The line that 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 advancement of that science. It has lately been done in natural philofophy: 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 ascertain

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ed: after which, it advances regularly, and fecutes the ground it has gained.

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Although 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 diftinguished 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, father than a defect of firft principles. Maný things were affumed under that character without a juft title: That nature abhors a vacuum; 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 thefe were affumed in the Peripatetic philofophy, without proof, as if they were felf-evident.

Des Cartes, fenfible of this weaknefs 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 that 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 those mental operations of which he was confcious: and having thus found fure footing in this one principle of confcioufness, he refted fatisfied with it, hoping to be able to build the whole fabric of his knowledge upon it; G 2

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