deavours to difcourage fallacious and unprofitable fpeculation, and to propofe a criterion by which it may be known and avoided?

But if reasoning ought not to be carried beyond a certain boundary, and if it is the authority of common fenfe that fixeth this boundary, and if it be poffible to miftake a prejudice for a principle of common fenfe, how (it may be faid) are prejudices to be detected? At this rate, a man has nothing to do, but to call his prejudice a dictate of common sense, and then it is established in perfect fecurity beyond the reach of argument. Doth not this furnish a pretence for limiting the freedom of inquiry?-Having already faid a great deal in anfwer to the first part of this question, I need not now fay much in answer to the laft. I fhall only afk, on the other hand, what method of reafoning is the propereft for overcoming the prejudices of an obftinate man? Are we to wrangle with him in infinitum, without ever arriving at any fixed principle? That is not the way to illuftrate truth, or rectify error. Do we propofe to afcertain the importance of our arguments by their 3 F 2 number,

number, and to pronounce that the bet

ter cause whofe champion gives the laft word? This, I fear, would not mend the matter. Suppofe our antagonist should deny a felf-evident truth, or refufe his af fent to an intuitive probability; must we not refer him to the common fenfe of mankind? If we do not, we muft either hold our peace, or have recourse to fophiftry: for when a principle comes to be intuitively true or falfe, all legitimate reafoning is at an end, and all further reafoning impertinent. To the common fenfe of mankind we must therefore refer him fooner or later; and if he continue obftinate, we must leave him. Is it not then of confequence to truth, and may it not serve to prevent many a fophiftical argument, and unprofitable logomachy, that we have it continually in view, that common fenfe is the ftandard of truth? principle which men are not always difpofed to admit in its full latitude, and which, in the heat and hurry of difpute, they are apt to overlook altogether. Some men will always be found, who think the moft abfurd prejudices founded ́in common fenfe. Reafonable men never fcruple

to

to fubmit their prejudices or principles to examination: but if that examination turn to no account, or if it turn to a bad account; if it only puzzle where it ought to convince, and darken what it ought to il luftrate; if it recommend impracticable modes of action, or inconceivable modes of thought;- I must confefs I cannot perceive the use of it. This is the only kind of reasoning that I mean to difcourage. It is this kind of reafoning which hath proved fo fatal to the abstract fciences. In it all our fceptical fystems are founded; of it they confift; and by it they are fupported. Till the abstract fciences be cleared of this kind of reafoning, they deferve not the name of philofophy: they may amufe a weak and turbulent mind, and render it ftill weaker and more turbulent; but they cannot convey any real inftruction: they may undermine the foundations of virtue and fcience; but they cannot illuftrate a fingle truth, nor establish one principle of importance, nor improve the mind of man in any refpect whatsoever.

By fome it may be thought an objection to the principles of this effay, "That they "feem to recommend a method of confu

"tation

"tation which is not ftrictly according to "logic, and do actually contradict fome "of the established laws of that science."

It will readily be acknowledged, that many of the maxims of the fchool-logic are founded in truth and nature, and have fo long obtained univerfal approbation, that they are now become proverbial in philofophy. Many of its rules and diftinctions are extremely useful, not fo much for ftrengthening the judgement, as for enabling the difputant quickly to comprehend, and perfpicuously to exprefs, in what the force or fallacy of an argument confifts. The ground-work of this fcience, the Logic of Ariftotle, if we may judge of the whole by the part now extant, is one of the most fuccessful and most extraordinary efforts of philofophic genius that ever appeared in the world. And yet, if we confider this fcience, with regard to its defign and confequences, we fhall perhaps fee reafon to think, that a strict obfervance of its laws is not always neceffary to the discovery of truth.

It was originally intended as a help to discourse among a talkative and sprightly people. The conftitution of Athens ren

dered

dered the art of public fpeaking of very great importance, and almoft a certain road to preferment or diftinction. This was alfo in fome measure the cafe at Rome; but the Romans were more referved, and did not, till about the time of Cicero, think of reducing converfation or public speaking to rule. The vivacity of the Athenians, encouraged by their democratical fpirit, made them fond of difputes and declamations, which were often carried on without any view to discover truth, but merely to gratify humour, give employment to the tongue, and amufe a vacant hour. Some of the dialogues of Plato are to be confidered in this light; rather as exercises in declamation, than ferious difquifitions in philofophy. It is true, this is not the only merit even of fuch of them as feem of leaft importance. If we are often diffatisfied with his doctrine; if we have little curiofity to learn the characters and manners of that age, whereof he hath given fo natural a reprefentation; we must yet acknowledge, that as models for elegance and fimplicity of compofition, the most inconfiderable of

Plato's