Abstract of a Trealife, entitled,

LOGIC; or, The ART of difcovering TRUTH.

Written in French by Father REGNAULT.

OGIC is a fcience convenient for all forts of perfons, and of use on

L almost all occafions of life. There are a thoufand things of which

we may fafely be ignorant, but it is of utmost importance to acquire a juftnefs in our thoughts, in our judgments, and ratiocinations. And as the end of this art is to preserve from error, and to teach how to discover truth, it must be acknowledg'd to be of infinite advantage in all conditions of life. The greateft part of mankind are unhappy only by forming falfe ideas of objects, judging erroneously, and reasoning abfurdly concerning them, and the happiness of others often depends on nothing but the justnefs of their thoughts and reflexions. We too commonly afcribe a great part of the calamities which befall us to our evil fortune, tho' they have no other fource than our falfe judgment. The happy fuccess of an enterprize, if not croffed by fome unforeseen event, must naturally depend on the just measures which are taken, and we never take fuch measures but in confequence of those ideas which we form of the nature of that enterprize. Self-love induces us to impute to chance and fortune, thofe ill events which we ought to afcribe wholly to our own defect of judgment, or want of difcernment. Chance is a phantom,which we endeavour to realife, in order to discharge ourselves of thofe faults which we commit.

All men are endu'd with a kind of Logic, tho' too imperfect to preferve them from error. And here it is that art comes in very feafonably to the affiftance of nature, by directing the mind in the right way for the discovery of truth. This fubject has been treated of more than once by great men, but not exhausted; it is a field of too vaft extent to fall within known limits. Some reflexions on what paffes before our eyes in the ordinary courfe of affairs, and within ourselves at the moment when we think, induced father Regnault to form a defign of adding fome new degree of perfection to this art. This work is in the taste of his Phyfical Dialogues between Ariflus and Eudoxus, who are also the perfons introduced as talkers in this piece. Some new notions, together with fome more antient, but vary'd, and fet in a new light, are capable of awakening the attention of the reader. We love now more than ever variety in things, and in the manner in which they are reprefented to the understanding.

His Logic has one great advantage, in that it is adapted to the capacity of all forts of people. A young perfon, who has had but a small taste of learning, may understand it without the help of a master. The author has defignedly avoided to burden it with a great number of rules, which rather fatigue than enlighten the understanding; he uses none but fuch as appear to be calculated for a book of common ufe, and rejects all fubtilties, which are rather ingenious than ufeful. In thus confining himself to what is fimply neceffary, he has comprehended in one moderate vo

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fume the best part of what is contain'd in all the books written upon the fubject.

There are in every fcience certain terms, of no ufe in the common affairs of life. Thofe which our author thought were neceffary to be u fed, he explains with much clearness and precifion. An exceffive delicacy is too apt to disdain fuch expreffions as are unfuited to it, or offenfive to the ear; and they might indeed be rejected, but 'twere better to retain them, to know their fignification, their force, and their value, that we may be in a condition to perceive the truth in good works, and to difcover error in fuch as are of a pernicious tendency.

Rules are not always fufficient for the understanding of truth, there is frequent need of examples, and of fuch too as are well chofen. Our author furnishes us with a good number of examples in his Logic, which befides has its maxims, and practical reflexions under proper heads, or, to lay all in a word, its method, which is extenfive, and of general ufe. In this method we are shown the path by which we muft arrive at diftant truths in proceeding step after ftep by degrees, fometimes from more fimple and eafy truths to thofe of a more difficult and complex nature, and fometimes in a contrary order, but always from known truths to unknown. We here learn what truths are most important in the discovery, the difficulties which attend it, and the way to furmount them, the art of informing ourfelves, and inftructing others, of fetting a queftion in a proper light, of exciting a curiofity of mind, and keeping it attentive, how to move concern, to act the critic without offence, to difpute to good effect, and even to write for the intereft of truth.

The independent ftrokes, and digreffive paffages which occur here and there in this converfation between Ariftus and Eudoxus are very proper to difpel that dulnefs and weariness, which are the ordinary effects of a dry and abftracted fubject. They are a kind of general meditations, in which the mind reflecting on the paffions of the heart, on the impreffions from external objects, and on what paffes within itself when it perceives, judges, or ratiocinates, difcovers the marks of the different forts of ideas, with the rules or laws of which they are fufceptible, in order to render them juft, clear, true and diftinét. Ariftus is a young man of a penetrating wit, and a happy memory, has a tafte for the fciences, with an ardent defire to learn the fecret of finding out the truth. Eudoxus is the perfon who undertakes to teach him this fecret.-Ariftus, being in fome fort engaged in meditations with Eudoxus, difcovers from his own manner of thinking the way to think justly. When he is thus led into the right method by Eudoxus, he makes difcoveries from time to time himself of truths, of which beofre he had only received hints from Eudoxus, the confident of his reflections, and conflant witnefs of his refearches, and has the pleasure of being able to aícribe to himelt fome merit in the discoveries which he makes. In this manner they both proceed as it were in concert to the very fource of our errors, in order to find a prefervative against them.

There are twelve of thefe dialogues, and their fubjects are as follows. The firft treats of Logic in general; the fecond, of the properties of ideas; the third, of rules relating to ideas; the fourth, of the expreffions of ideas. The fifth dialogue concerns the properties of judgment; the fixth is on the different kinds of propofitions; the feventh relates to

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propofitions compared one with another; the eighth, to the rules or laws of judgment; the ninth is on the fources of falfe judgment. The tenth has for its fubject the properties of ratiocination; the eleventh its laws; and the laft dialogue is upon method.

The first is very fhort; it begins with fome inftances of the cleareft truths, which frequently go by the name of first principles or axioms. When you fay what is, is, you fpeak a truth, and at the fame time a truth the most fimple, clear and intelligible, because we readily conceive that it is impoffible for a thing to be and not to be at the fame time. These forts of truths are easily discover'd, but there are others more difficult to be understood, and not discoverable but by a particular direction of the operations of the mind, which is the fubject of the rest of this dialogue.

In the fecond, the author firft explains, in a very clear manner, the terms object, perception, fenfation, imagination, inward fentiment or conSciousness, attention and idea. In all these he is very distinct and parti cular, and illuftrates what he fays with a great number of examples. To form a notion of the argument and method of this dialogue, take the following short abstract.

Logic is the art of difcovering truth. Truth is difcover'd by the operations of the mind. The firft operation of the mind is perception, or an idea. An idea, or perception, is a fimple view, a notion, which neither affirms nor denies, nor determines any thing. I fee a flower, I think on God, without determining any thing concerning the divine nature and perfections, or concerning the flower; this is perception. According to the different objects, or different manner of perceiving, Percep tion is diftinguifhed into fenfation, imagination, fentiment, confciousness, attention and idea. Senfation is when we perceive the fenfible qualities of bodies, by the present action of outward objects upon the fenfes. Imagi nation is when we perceive these fenfible qualities, without the present action of external objects upon the fenfes. Sentiment is when we experience within ourselves fome affection, fome paffion; for inftance, joy, or fadnels. Confcioufnefs is when we have a knowledge of the exiftence of the modes of our foul, of its affections, its paffions, and its though:s, without knowing the nature or properties, in fuch a manner as to be able clearly to explain ourfelves upon the fubje&t. Attention is a strong and conftant perception; and idea is when we have a conception of the nature and properties of things, fo as to be able clearly to unfold and explain them. To illuftrate the fame by examples in each operation: The fight of a blue firmament, befpangled with flars, is fenfation; the remembrance of a fpectacle, imagination; joy or forrow, fentiment; the knowledge of our fentiments, imaginations, &c. confcioufness, or inward fentiment; the conftant view of a danger which threatens us, or of fomething good which concerns us, and which we expect, attention; the idea of God, justice, the number four, fix, idea in its proper fenfe. There is an idea of substance, and an idea of mode. Here the author gives us a definition of fubftance, and mode. The effence, nature, and foundation of every thing is the object of a pure idea, or idea taken in its proper fenfe. Sometimes it is a fingular idea, or fuch as prefents to the mind a fingle, determinate, fixed object, as the idea of Eudoxus; fometimes it is an univerfal idea, or what agrees to several objects, both in general and particular, as the idea of a flower,

which agrees indifferently to all flowers, and to the Anemone, Jonquil, Tulip and Amaranthus in particular.

A fingular idea contains univerfal ideas, which upon examination disclose themselves; and these univerfal ideas comprehend others more general than themselves. Thus from the idea of Eudoxus arises the idea of man, from that of man the idea of animal, whence we have the idea of being, which is a barren idea productive of nothing farther. The idea then of being alone is fimple properly speaking, the others are complex. Thefe complex ideas have their proper foundation and extent. The foundation of a complex idea is the conjunction of the ideas comprehended under it; as the collection of the feveral ideas of rational, animal, substance, &c. is the foundation of the idea of man. The extent of an idea is its relation to individuals; thus the extent of the idea of man is the relation of that idea to Ariftus, Eudoxus, &c. Several complex ideas discover to us several perfections in the fame object. The general ideas, with relation to the different perfections which difplay themselves in the fame object, are the genus, Species, difference, property and accident. The most general of thefe ideas is that of genus; that of Species is lefs general; an idea which limits or determines the genus to fuch a fpecies is a difference; an idea of a perfection which is effential, or arifing from the fundamental conftitution of the fpecies is a property, and the idea of an accidental quality an accident. We give the fame names to the different objects of thefe ideas. Of ideas, whether general or not general, fome are abfolute, others relative. The former prefent only their bare object to the mind, as the idea of a circle; the other excite other ideas, as the idea of a creature raises in the mind the idea of a creator; the former appears folitary and alone, the other always in company.

Different kinds of ideas have different properties and qualities, as fome are clear, others obfcure, fome true, others falfe, fome lively, others faint, fome diftinct, others confus'd. Clear ideas difcover to the mind the most inward parts of their object, or its very nature, which obfcure ideas fail of doing. True ideas reprefent their object fuch as it really is; falfe ideas fhew it with fuch properties as belong not to it. Lively ideas strongly attract the attention of the mind to their object; faint ideas fcarcely attract at all, or are incapable of fixing the attention. Diftinct ideas exhibit their object clearly and eafily diftinguishable from others; confufed, on the contrary, represent the fame in a diforderly and indistinct manner.

We have given you the fubitance of the 2d dialogue: In the 3d the author gives us rules which may be highly serviceable to us for obtaining fuch ideas as are clear, juft, regular, proper, true, and free from illufion. It is not only requir'd to have thefe ideas, but to know how to exprefs them by words, when we would make ourselves understood; thefe words, or terms, which are in ufe among Logicians, are the fubject of the 4th dialogue.

The defign of the 5th is to explain the nature, with the different kids and properties of judgment, which our author defines a determination of the mind on the relation which it perceives between the objects of its ideas. Three things therefore are to be confider'd in judgment.

1. The ideas in the mind, which are two at leaft; 2. The compa rifon of those ideas; 3. The perception of fome relation of agreement or disagreement in their objects; which is fucceeded by a determination. If it be here asked, whether judgment be the perception itself of the relation; in answer to this question it is fufficient to reflect on what paffes within us, when we form a judgment or determination. The perfon who determines is fenfible that his mind adds fomething to perception, and even that a relation may be perceiv'd on which no judgment may pass at all. Two perfons fee a-far off a square tower; it appears round to both, because of the distance. One of them, who never faw it near, judges it to be round by the appearance; the other, who has feen it near, and knows it is fquare, does not judge it to be round; otherwise he would judge it to be round and not round at the fame time. Judgment therefore is not perception itself, but fupposes it, and is a kind of second thought, in which we affirm or deny the relation of the object of one idea to the object of another idea. Hence there are two forts of judgment; one affirmative, by which we affirm, as when we fay God is just; the other negative, by which we deny, as when it it faid God is no deceiver.

The fixth dialogue treats of the different kinds of propofitions, and is naturally confequent from the former, for there is no judgment without a propofition. This dialogue is hardly capable of an extract; it contains too many particulars, and, what is more, fuch particulars as form a chain which cannot well be broken. The fame may be said of the feventh, in which the author compares together the different kinds of propofitions. The comparison is well connected, and it is hard to fay whether the reader has moft reason to be pleased with Ariftus or Eudoxus, who both of them acquit themfelves perfectly well of their respective parts. In the eighth dialogue, which concerns the rules or laws of judgment, we meet with very judicious remarks on definitions, and the relation of ideas to one another, of excellent ufe in all fciences.

There is perhaps nothing which deferves to be more regarded than the precepts in the ninth dialogue, in which the author exposes the fources of falfe judgment. These fources are not far diftant from us. We must fearch for them in ourselves, and in our neighbourhood. They may be found in impatience, floth, temperament, vanity, inconfancy, prejudice, cuftom, in the fenfes, in love and hatred, in the paffions, as well as in what affects them.

We find their fources (1) in impatience; for in order to a found judgment there is requir'd a difcernment of relations. Ideas are involved one within another, and it requires time to divide, unfold, and range them in proper order. There is need of patience to dwell long upon the fame object, to confider it in all its appearances, and examine it on all fides; and we are too apt to be impatient. The mind is foon tir'd in its purfuits, if unattended with pleasure, and cares not to employ itself but on ideas whofe relations are obvious and eafy to be apprehended. It frequently loses even the memory of others, and takes an affociation of fome partial ideas for the ideas themselves; it supposes a perfect where there is but a partial refemblance, paffes a judgment on fuch weak grounds, and too late finds itself in an error.

2. Another