If any thing be a stone, the same is not a living creature,
Therefore, If any thing be a stone, the same is not a man,
Or, If any thing be a man, the same is not a stone.
And thus much seems sufficient for the nature of syllogisms; (for the doctrine of moods and figures is clearly delivered by others that have written largely and profitably of the same). Nor are precepts so necessary as practice for the attaining of true ratiocination; and they that study the demonstrations of mathematicians, will sooner learn true logic, than they that spend time in reading the rules of syllogizing which logicians have made; no otherwise than little children learn to go, not by precepts, but by exercising their feet. This, therefore, may serve for the first pace in the way to Philosophy.
In the next place I shall speak of the faults and errors into which men that reason unwarily are apt to fall; and of their kinds and causes.
CHAPTER V.
OF ERRING, FALSITY, AND CAPTIONS.
[1.] Erring and falsity how they differ. Error of the mind by itself without the use of words, how it happens.—[2.] A sevenfold incoherency of names, every one of which makes always a false proposition.—[3.] Examples of the first manner of incoherency.—[4.] Of the second.—[5.] Of the third.—[6.] Of the fourth.—[7.] Of the fifth.—[8.] Of the sixth.—[9.] Of the seventh.—[10.] Falsity of propositions detected by resolving the terms with definitions continued till they come to simple names, or names that are the most general of their kind.—[11.] Of the fault of a syllogism consisting in the implication of the terms with the copula.—[12.] Of the fault which consists in equivocation.—[13.] Sophistical captions are oftener faulty in the matter than in the form of syllogisms.
Erring & falsity how they differ. Error of the mind by itself, without the use of words, how it happens.
1. Men are subject to err not only in affirming and denying, but also in perception, and in silent cogitation. In affirming and denying, when they call any thing by a name, which is not the name thereof; as if from seeing the sun first by reflection in water, and afterwards again directly in the firmament, we should to both those appearances give the name of sun, and say there are two suns; which none but men can do, for no other living creatures have the use of names. This kind of error only deserves the name of falsity, as arising, not from sense, nor from the things themselves, but from pronouncing rashly; for names have their constitution, not from the species of things, but from the will and consent of men. And hence it comes to pass, that men pronounce falsely, by their own negligence, in departing from such appellations of things as are agreed upon, and are not deceived neither by the things, nor by the sense; for they do not perceive that the thing they see is called sun, but they give it that name from their own will and agreement. Tacit errors, or the errors of sense and cogitation, are made, by passing from one imagination to the imagination of another different thing; or by feigning that to be past, or future, which never was, nor ever shall be; as when, by seeing the image of the sun in water, we imagine the sun itself to be there; or by seeing swords, that there has been or shall be fighting, because it uses to be so for the most part; or when from promises we feign the mind of the promiser to be such and such; or lastly, when from any sign we vainly imagine something to be signified, which is not. And errors of this sort are common to all things that have sense; and yet the deception proceeds neither from our senses, nor from the things we perceive; but from ourselves while we feign such things as are but mere images to be something more than images. But neither things, nor imaginations of things, can be said to be false, seeing they are truly what they are; nor do they, as signs, promise any thing which they do not perform; for they indeed do not promise at all, but we from them; nor do the clouds, but we, from seeing the clouds, say it shall rain. The best way, therefore, to free ourselves from such errors as arise from natural signs, is first of all, before we begin to reason concerning such conjectural things, to suppose ourselves ignorant, and then to make use of our ratiocination; for these errors proceed from the want of ratiocination; whereas, errors which consist in affirmation and negation, (that is, the falsity of propositions) proceed only from reasoning amiss. Of these, therefore, as repugnant to philosophy, I will speak principally.