Gardiners upon the fame Principle can foretel the Months when every Plant will be in Bloom, and the Plowman knows the Weeks of Harvest: We are fure if there be a Chicken, there was an Egg: If there be a Rainbow, we are certain it rains not far off: If we behold a Tree growing on the Earth, we know it has naturally a Root under Ground.

3. Where there is fuch a necessary Connection between Causes and Effects, Antecedents and Confequents, Signs and Things fignified, we know alfo that like Caufes will have like Effects, and proportionable Caufes will have proportionable Effects, contrary Caufes will have contrary Effects; and obferving Men may form' many Judgments by the Rules of Similitude and Proportion, where the Caufes, Effects, &c. are not entirely the fame.

4. Where there is but a probable and uncertain Connection between Antecedents, Concomitants and Confequents, we can give but a Conjecture, or a probable Determination. If the Clouds gather, or the Weather-glass finks, we fuppofe it will rain: If a Man fpit Blood frequently with coughing, we fuppofe his Lungs are burt: If very dangerous Symptoms appear, we expect his Death.

5. Where Caufes operate freely with a Liberty of Indifference to this or the contrary, there we cannot certainly know what the Effects will be: For it feems to be contingent, and the certain Knowledge of it belongs only to God. This is the Cafe in the greatest Part of human Actions.

6. Yet wife Men by a juft Obfervation of human Nature will give very probable Conjectures in this Matter alfo concerning Things paft, or Things future, because human Nature in all Ages and Nations has fuch a Conformity to itself. By a Knowledge of the Tempers of Men and their prefent Circumstances, we may be able to give a

happy

happy Guess what their Conduct will be, and what will be the Event, by an Obfervation of the like Cafes in former Times. This made the Emperor Marcus Antoninus to fay, "By looking back into "Hiftory, and confidering the Fate and Revolutions "of Governments, you will be able to form a Guess, and almost prophesy upon the future. For Things past, prefent, and to come, are strangely uniform, "and of a Colour; and are commonly caft in the Jame Mould. So that upon the Matter, forty "Years of buman Life may ferve for a Sample of "ten thousand." Collier's Antoninus, Book VII, Sect. 50.

7. There are alfo fome other Principles of judging concerning the paft Actions of Men in former Ages, befides Books, Hiftories, and Traditions, which are the Mediums of conveying human Teftimony; as we may infer the Skill and Magnificence of the Antients by fome Fragments of their Statues, and Ruins of their Buildings. We know what Roman Legions came into Great Britain by Numbers of Bricks dug out of the Earth in fome Parts of the Island, with the Marks of fome particular Legion upon them, which must have been employed there in Brick-making. We rectify fome Miftakes in History by Statues, Coins, old Altars, Utenfils of War, &c. We confirm or difprove fome pretended Traditions and historical Writings, by Medals, Images, Pictures, Urns, &c.

Thus I have gone thro' all thofe particular Objects of our Fudgment which I first propofed, and have laid down Principles and Rules by which we may fafely conduct ourselves therein. There is a Variety of other Objects concerning which we are occafionally called to pafs a Judgment, (viz.) The Characters of Perfons, the Value and Worth

of

of Things, the Sense and Meaning of particular Writers, Matters of Wit, Oratory, Poesy, Matters of Equity in judicial Courts, Maiters of Traffick and Commerce betwixt Man and Man, which would be endless to enumerate. But if the general and fpeeial Rules of Judgment which have been mentioned in these two last Chapters are treasured up in the Mind, and wrought into the very Temper of our Souls in our younger Years, they will lay a Foundation for just and regular Judgment concerning a thousand fpecial Occurrences in the religious, civil and learned Life.

THE

279

THE

THIRD PART

OF

LOGIC K.

A

Of Reafoning and Syllogifm.

S the first Work of the Mind is Perception, whereby our Ideas are framed, and the fecond is Judgment, which joins or disjoins our Ideas, and forms a Propofition, fo the third Operation of the Mind is Reasoning, which joins feveral Propofitions together, and makes a Syllogifm, that is, an Argument whereby we are wont to infer fomething that is lefs known, from Truths which are more evident.

3. The Doctrine of Sophisms, or false Reasoning, together with the Means of avoiding them, and the Manner of folving or anfwering them.

4. Some general Rules to direct our Reasoning.

CHAP. I.

Of the Nature of a Syllogifm, and the Parts of which it is compofed.

F the mere Perception and Comparison of two IIdeas would always fhew us whether they agree or difagree, then all rational Propofitions would be Matters of Intelligence, or first Principles, and there would be no Ufe of Reasoning, or drawing any Confequences. It is the Narrowness of the human Mind which introduces the Neceffity of Reafoning. When we are unable to judge of the Truth or Falfhood of a Propofition in an immediate Manner, by the mere Contemplation of its Subject and Predicate, we are then conftrained to ufe a Medium, and to compare each of them with fome third Idea, that by feeing how far they agree or disagree with it, we may be able to judge how far they agree or difagree among themselves: As, if there are two Lines A and B, and I know not whether they are equal or no, I take a third Line C, or an Inch, and apply it to each of them; if it agree with them both, then I infer that A and B are equal; but if it agree with one and not with the other, then I conclude A and B are unequal: If it agree with neither of them, there can be no Comparison,