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Thus the second chapter is finished, and a particular account given of all the chief kinds of syllogisms or arguments which are made use of among men, or treated of in Logic, together with special rules for the forination of them, as far as is necessary.
If a syllogism agrees with the rules which are given for the construction and regulation of it, it is called a true argument : if it disagrees with these rules, it is a paralogism or false argument : but when a false argument puts on the face and appearance of a true one, then it is properly called a sophism or fallacy, which shall be the subject of the next chapter
CHAP. III.-The Doctrine of Sophisms. FROM truth nothing can really follow but what is true : whensoever therefore we find a false conclusion drawn from preinises which seem to be true, there must be some fault in the dedaction or inference ; or else one of the premises is not true in the sense in which it is used in that argument.
When an argument carries the face of truth with it, and yet leads us into mistake, it is a sophism ; and there is some need of a particular description of these fallacious arguments, that we may with more ease and readiness detect and solve them. Sect. I.--Of several Kinds of Sophisms, and their Solution.
AS the rules of right judgment, and of good ratiocination, often coincide with each other, so the doctrine of prejudices, which was treated of in the second part of Logic, has anticipated a great deal of what might be said on the subject of sophisms; yet I shall mention the most remarkable springs of false argumentation, which are reduced by logicians to some of the following heads.
I. The first sort of sophism is called ignoratio elenchi, or a mistake of the question; that is, when something else is proved which has neither any necessary conuexion or consistency with the thing enquired, and consequently gives no determination to the enquiry, though it may seem at first sight to determine the question ; as, if any should conclude that St. Paul was not a native Jew, by proving that he was born a Roman ; or if they should pretend to determine that he was neither Roman nor Jew, by proving that he was born at Tarsus in Cilicia, these sophisms are refuted by shewing that all these three may be true; for he was born of Jewish parents in the city of Tarsus, and by some peculiar privilege granted to his parents, or his native city, he was born a denizen of Rome. Thus there is neither of these three characters of the apostle inconsistent with earlı other, and therefore the proving one of them true does not refute the others.
Or if the question be proposed, Whether the excess of wine
can be hurtful to him that drinks it, and the sophister should prove that it revives his spirits, it exbilarates his soul, it gives a man courage, and makes him strong and active, and then he takes it for granted that he has proved his point.
But the respondent may easily shew, that though wine may do all this, yet it may be finally hurtful buth to the soul and body of him that drinks it to excess.
Disputers when they grow warm, are ready to run into this fallacy; they dress up the opinion of their adversary as they please, and ascribe sentiments to him which he doth not acknowledge ; and when they have with a great deal of pomp attacked and confounded these images of straw of their own making, they triumph over their adversary as though they had utterly confuted his opinion.
It is a fallacy of the same kind which a disputant is guilty of, when he finds that his adversary is too hard for him, and that he cannot fairly prove the question first proposed; he then with sly, ness and subtlety turns the discourse aside to some other kiadred point which he can prove, and exults in that new argument 'wherein bis opponent never contradicted him.
The way to prevent this fallacy is by keeping the eye fixed on the precise point of dispute, and neither wandering from it ourselves, nor suffering our antagonist to wander from it, or substitute any thing else in its room.
II. The next sophism is called petitio principii, or a supposition of what is not granted ; that is, when any proposition is proved by the same proposition in other words, or by something that is equally uncertain and disputed ; as if any one undertake to prove iliat the human soul is extended through all parts of the body because it resides in every member, whiclı is but the same thing in other words : Or, if a Papist should pretend to prove ahat his religion is the only Catholic religion; and is derived from *Christ and his apostles, « because it agrees with the doctrine of all the fathers of the church, all the holy martyrs, and all the
Christian world throughout all ages ;" whereas this is the great point in contest, whether their religion does agree with that of all the ancients and the primitive Christians, or no.
III. That sort of fallacy which is called a circle, is very near' a-kin to the petitio principii; as when one of the premises
in a syllogism is questioned and opposed, and we intend to prove 'it by the conclusion; or, when in a train of syllogisms we prove the last by recurring to what was the conclusion of the first. The Papists are famous at this sort of fallacy, when they prove the scripture to be the word of God by the authority or infallible testimony of their church ; and when they are called to shew the infallible authority of their church; they pretend to prove it by the scripture.
IV. The next kind of sophism is called non causa pro causa or the assignation of a false cause. This the peripatetic philosophers were guilty of continually, when they told us that certain beings, which they called substantial forms, were the springs of colour, motion, vegetation, and the various operations of natural beings in the animate and inanimate world; when they informed us that nature was terribly afraid of a vacuum; and that this was the cause why the water would not fall out of a long tube if it was turned upside down; the moderns as well as the ancients fall often into this fallacy, when they positively assign the reasons of natural appearances, without sufficient experiments to prove them.
Astrologers are over-run with this sort of fallacies, and they cheat the people grossly by pretending to tell fortunes, and to deduce the cause of the various occurrences in the lives of men from the various positions of the stars and planets, which they call aspects.
When comets and eclipses of the sun and moon are construed to signify the fate of princes, the revolution of states, famine, wars and calamities of all kinds, it is a fallacy that belongs to this rank of sophisms.
There is scarce any thing more common in human life than this sort of deceitful argument. If any two accidental events happen to concur, one is presently made the cause of the other. “ If Titius wronged his neighbour of a guinea, and in six months after he fell down and broke his leg," weak men will impute it to the divine vengeance on Titius for his former injustice. This sophism was found also in the early days of the world; for when holy Job was surrounded with uncommon mi. series, his own friends inferred, that he was a most heinous criminal, and charged him with aggravated guilt as the cause of his calamities; though God himself by a voice from heaven solved this uncharitable sophism, and cleared his servant Job of that charge.
How frequent is it among men to impute crimes to wrong persons? We too often charge that upon the wicked contrivance and premeditated malice of a neighbour, which arose merely froin ignorance, or from an unguarded temper. And on the other hand when we have a mind to excuse ourselves, we practise the same sophism and charge that upon our inadvertence or our ignorance, which perhaps was designed wickedness. What is really done by a' necessity of circumstances, we sometimes impute to choice. And again, we charge that upon necessity which was really desired and chosen.
Sometimes a person acts out of judgment, in opposition to liis inclination; another person perliaps; acts the same thing out of inclination, and against his judgment. It is hard for us to
determine with assurance, what are the inward springs and secret causes of every man's conduct ; and therefore we should · be cautious and slow in passing a judgment where the case is not exceeding evident: and if we should mistake, let it rather be on the charitable, than on the censorious side.
It is the same sophism that charges mathematical learning with leading the minds of men to scepticism and infidelity, and as unjustly accuses the new philosophy of paving the way to heresy and schism. Thus the reformation from Popery has been charged with the murder and blood of millions, which in truth is to be imputed to the tyranny of the princes and the priests, who would not suffer the people to reform their sentiments and their practices according to the word of God. Thus Christianity in the primitive ages was charged by the heathens with all the calamities which befel the Roman Empire, because the Christians renounced the heathen gods and idols.
The way to relieve ourselves from those sophisms, and to secure ourselves from the danger of falling into them is an honest and diligent enquiry into the real nature and causes of things, with a constant watchfulness against all those prejudices that inight warp. the judgment aside from truth in that enquiry.
V. The next is called fallacia-accidentis, or a sophisin wherein we pronounce concerning the nature and essential properties of any subject according to something which is merely accidental to it.' This is a-kin to the former, and is also very frequent in human life. So if Opium or the Peruvian bark has been used imprudently or unsuccessfully, whereby the patient has received injury, some weaker people absolutely pronounce against the use of the bark or opium upon all occasions whatsoever, and are ready to call them poison. So wine has been the accidental occasion of drunkenness and quarrels; learning and printing may have been the accidental cause of sedition in a state? the reading of the bible, by accident, has been abused to promote heresies or destructive errors ; and for these reasons they have all been pronounced evil things. Mahomet forbade his followers the use of wine; the Turks discourage learning in their dominion; and the Papists forbid the scripture to be read by the Laity. Bat how very unreasonable are these inferences, and these prohibitions which are built upon them!
VI. The next sophism borders upon the former; and that is, when we argue from ihat which is true in particular circumstances, to prove the same thing true absolutely, simply, and ab. stracted from all circumstances; this is called in the schools a sophism, a dicto secundum quid ad dictum simpliciter : as, That which is bought in the shambles is eaten for dinner, raw meat is bought in the shambles; therefore raw meat is eaten for dimer. Or thus, Livy writes fables and improbabilities, when he describes
prodiges and omens; therefore Livy's Roman history is never to be believed in any thing. Or thus, There may be coine mistake of transcribers in some part of scripture; therefore scripture alone is not a safe guide for our faith.
This sort of sophism has its recerse also ; as when we argue from that which is true simply and absolutely, to prove the same thing true in all particular circumstances whatsoever* ; as if a traitor should argue from the sixth commandment, Thou shalt not kill a man, to prove that he himself ought not to be hanged: or if a madman should tell me, I ought not to withhold his sword from him, because no man ought to withhold the property of another.
These two last species of sophisms are easily solved, by shewing the difference betwixt things in their absolute nature, and the same things surrounded with peculiar circumstances, and considered in regard to special times, places, persons and occasions ; or by shewing the difference between a moral and a metaphysical universality, and that the proposition will hold good in one case, but not in the other.
VII. The sophisms of composition and division come next to be mentioned.
The soplism of composition is when we infer any thing concerning ideas in a compounded sense, which is only true in a divided sense. And when it is said in the gospel that Christ made the blind to see, and the deaf to hear, and the lame to walk, we ought not to infer hence that Christ performed contradictions ; but those wbo were blind before, were made to see, and those who were deaf before, were made to hear ; &o. So when the scripture assures us, the worst of sinners may be saved ; it signifies only, that they who have been the worst of sinners may repent'and be saved, not that they shall be saved in their sins. Or if any one should argue thus, Two and three are even and odd; five are two and three; therefore five are even and odd. Here that is very falsely inferred concerning two and three in union, which is only true of them divided.
The sophism of division is when we infer the same thing concerning ideas in a divided sense, which is only true ia a.compounded sense; as, if we should pretend to prove that every soldier in the Grecian army put an hundred thousand Persians to flight, because the Grecian soldiers did so.
Or if a man should argue thus, five is one number; two and three are five; therefore two and three are one number.
This sort of sophisms is committed when the word all is taken in a collective and a distributive sense, without a due dis
* This is arguing from'a moral voiversalitv, which admits of some exceptioas, in the same manner as may be argued from metaphysical or a natural :uiversality, which admits of no exception.