The Extension.—This consists in carrying your opponent's proposition beyond its natural limits; in giving it as general a signification and as wide a sense as possible, so as to exaggerate it; and, on the other hand, in giving your own proposition as restricted a sense and as narrow limits as you can, because the more general a statement becomes, the more numerous are the objections to which it is open. The defence consists in an accurate statement of the point or essential question at issue.
Example 1.—I asserted that the English were supreme in drama. My opponent attempted to give an instance to the contrary, and replied that it was a well-known fact that in music, and consequently in opera, they could do nothing at all. I repelled the attack by reminding him that music was not included in dramatic art, which covered tragedy and comedy alone. This he knew very well. What he had done was to try to generalise my proposition, so that it would apply to all theatrical representations, and, consequently, to opera and then to music, in order to make certain of defeating me. Contrarily, we may save our proposition by reducing it within narrower limits than we had first intended, if our way of expressing it favours this expedient.
Example 2.—A. declares that the Peace of 1814 gave back their independence to all the German towns of the Hanseatic League. B. gives an instance to the contrary by reciting the fact that Dantzig, which received its independence from Buonaparte, lost it by that Peace. A. saves himself thus: "I said 'all German towns,' and Dantzig was in Poland."
This trick was mentioned by Aristotle in the Topica (bk. viii., cc. 11, 12).
Example 3.—Lamarck, in his Philosophic Zoologique (vol. i., p. 208), states that the polype has no feeling, because it has no nerves. It is certain, however, that it has some sort of perception; for it advances towards light by moving in an ingenious fashion from branch to branch, and it seizes its prey. Hence it has been assumed that its nervous system is spread over the whole of its body in equal measure, as though it were blended with it; for it is obvious that the polype possesses some faculty of perception without having any separate organs of sense. Since this assumption refutes Lamarck's position, he argues thus: "In that case all parts of its body must be capable of every kind of feeling, and also of motion, of will, of thought. The polype would have all the organs of the most perfect animal in every point of its body; every point could see, smell, taste, hear, and so on; nay, it could think, judge, and draw conclusions; every particle of its body would be a perfect animal and it would stand higher than man, as every part of it would possess all the faculties which man possesses only in the whole of him. Further, there would be no reason for not extending what is true of the polype to all monads, the most imperfect of all creatures, and ultimately to the plants, which are also alive, etc., etc." By using dialectical tricks of this kind a writer betrays that he is secretly conscious of being in the wrong. Because it was said that the creature's whole body is sensitive to light, and is therefore possessed of nerves, he makes out that its whole body is capable of thought.
The Homonymy.—This trick is to extend a proposition to something which has little or nothing in common with the matter in question but the similarity of the word; then to refute it triumphantly, and so claim credit for having refuted the original statement.
It may be noted here that synonyms are two words for the same conception; homonyms, two conceptions which are covered by the same word. (See Aristotle, Topica, bk. i., c. 13.) "Deep," "cutting," "high," used at one moment of bodies at another of tones, are homonyms; "honourable" and "honest" are synonyms.
This is a trick which may be regarded as identical with the sophism ex homonymia; although, if the sophism is obvious, it will deceive no one.
Every light can be extinguished. The intellect is a light. Therefore it can be extinguished.
Here it is at once clear that there are four terms in the syllogism, "light" being used both in a real and in a metaphorical sense. But if the sophism takes a subtle form, it is, of course, apt to mislead, especially where the conceptions which are covered by the same word are related, and inclined to be interchangeable. It is never subtle enough to deceive, if it is used intentionally; and therefore cases of it must be collected from actual and individual experience.
It would be a very good thing if every trick could receive some short and obviously appropriate name, so that when a man used this or that particular trick, he could be at once reproached for it.
I will give two examples of the homonymy.
Example 1.—A.: "You are not yet initiated into the mysteries of the Kantian philosophy."
B.: "Oh, if it's mysteries you're talking of, I'll have nothing to do with them."
Example 2.—I condemned the principle involved in the word honour as a foolish one; for, according to it, a man loses his honour by receiving an insult, which he cannot wipe out unless he replies with a still greater insult, or by shedding his adversary's blood or his own. I contended that a man's true honour cannot be outraged by what he suffers, but only and alone by what he does; for there is no saying what may befall any one of us. My opponent immediately attacked the reason I had given, and triumphantly proved to me that when a tradesman was falsely accused of misrepresentation, dishonesty, or neglect in his business, it was an attack upon his honour, which in this case was outraged solely by what he suffered, and that he could only retrieve it by punishing his aggressor and making him retract.
Here, by a homonymy, he was foisting civic honour, which is otherwise called good name, and which may be outraged by libel and slander, on to the conception of knightly honour, also called point d'honneur, which may be outraged by insult. And since an attack on the former cannot be disregarded, but must be repelled by public disproof, so, with the same justification, an attack on the latter must not be disregarded either, but it must be defeated by still greater insult and a duel. Here we have a confusion of two essentially different things through the homonymy in the word honour, and a consequent alteration of the point in dispute.
Another trick is to take a proposition which is laid down relatively, and in reference to some particular matter, as though it were uttered with a general or absolute application; or, at least, to take it in some quite different sense, and then refute it. Aristotle's example is as follows:
A Moor is black; but in regard to his teeth he is white; therefore, he is black and not black at the same moment. This is an obvious sophism, which will deceive no one. Let us contrast it with one drawn from actual experience.
In talking of philosophy, I admitted that my system upheld the Quietists, and commended them. Shortly afterwards the conversation turned upon Hegel, and I maintained that his writings were mostly nonsense; or, at any rate, that there were many passages in them where the author wrote the words, and it was left to the reader to find a meaning for them. My opponent did not attempt to refute this assertion ad rem, but contented himself by advancing the argumentum ad hominem, and telling me that I had just been praising the Quietists, and that they had written a good deal of nonsense too.
This I admitted; but, by way of correcting him, I said that I had praised the Quietists, not as philosophers and writers, that is to say, for their achievements in the sphere of theory, but only as men, and for their conduct in mere matters of practice; and that in Hegel's case we were talking of theories. In this way I parried the attack.
The first three tricks are of a kindred character. They have this in common, that something different is attacked from that which was asserted. It would therefore be an ignoratio elenchi to allow oneself to be disposed of in such a manner.
For in all the examples that I have given, what the opponent says is true, but it stands in apparent and not in real contradiction with the thesis. All that the man whom he is attacking has to do is to deny the validity of his syllogism; to deny, namely, the conclusion which he draws, that because his proposition is true, ours is false. In this way his refutation is itself directly refuted by a denial of his conclusion, per negationem consequentiae. Another trick is to refuse to admit true premisses because of a foreseen conclusion. There are two ways of defeating it, incorporated in the next two sections.
If you want to draw a conclusion, you must not let it be foreseen, but you must get the premisses admitted one by one, unobserved, mingling them here and there in your talk; otherwise, your opponent will attempt all sorts of chicanery. Or, if it is doubtful whether your opponent will admit them, you must advance the premisses of these premisses; that is to say, you must draw up pro-syllogisms, and get the premisses of several of them admitted in no definite order. In this way you conceal your game until you have obtained all the admissions that are necessary, and so reach your goal by making a circuit. These rules are given by Aristotle in his Topica, bk. viii., c. 1. It is a trick which needs no illustration.
To prove the truth of a proposition, you may also employ previous propositions that are not true, should your opponent refuse to admit the true ones, either because he fails to perceive their truth, or because he sees that the thesis immediately follows from them. In that case the plan is to take propositions which are false in themselves but true for your opponent, and argue from the way in which he thinks, that is to say, ex concessis. For a true conclusion may follow from false premisses, but not vice versâ. In the same fashion your opponent's false propositions may be refuted by other false propositions, which he, however, takes to be true; for it is with him that you have to do, and you must use the thoughts that he uses. For instance, if he is a member of some sect to which you do not belong, you may employ the declared, opinions of this sect against him, as principles. 
[Footnote 1: Aristotle, Topica bk. viii., chap. 2.]
Another plan is to beg the question in disguise by postulating what has to be proved, either (1) under another name; for instance, "good repute" instead of "honour"; "virtue" instead of "virginity," etc.; or by using such convertible terms as "red-blooded animals" and "vertebrates"; or (2) by making a general assumption covering the particular point in dispute; for instance, maintaining the uncertainty of medicine by postulating the uncertainty of all human knowledge. (3) If, vice versâ, two things follow one from the other, and one is to be proved, you may postulate the other. (4) If a general proposition is to be proved, you may get your opponent to admit every one of the particulars. This is the converse of the second. 
[Footnote 1: Idem, chap. 11. The last chapter of this work contains some good rules for the practice of Dialectics.]
Should the disputation be conducted on somewhat strict and formal lines, and there be a desire to arrive at a very clear understanding, he who states the proposition and wants to prove it may proceed against his opponent by question, in order to show the truth of the statement from his admissions. The erotematic, or Socratic, method was especially in use among the ancients; and this and some of the tricks following later on are akin to it. 
[Footnote 1: They are all a free version of chap. 15 of Aristotle's De Sophistici Elenchis.]
The plan is to ask a great many wide-reaching questions at once, so as to hide what you want to get admitted, and, on the other hand, quickly propound the argument resulting from the admissions; for those who are slow of understanding cannot follow accurately, and do not notice any mistakes or gaps there may be in the demonstration.
This trick consists in making your opponent angry; for when he is angry he is incapable of judging aright, and perceiving where his advantage lies. You can make him angry by doing him repeated injustice, or practising some kind of chicanery, and being generally insolent.
Or you may put questions in an order different from that which the conclusion to be drawn from them requires, and transpose them, so as not to let him know at what you are aiming. He can then take no precautions. You may also use his answers for different or even opposite conclusions, according to their character. This is akin to the trick of masking your procedure.
If you observe that your opponent designedly returns a negative answer to the questions which, for the sake of your proposition, you want him to answer in the affirmative, you must ask the converse of the proposition, as though it were that which you were anxious to see affirmed; or, at any rate, you may give him his choice of both, so that he may not perceive which of them you are asking him to affirm.
If you make an induction, and your opponent grants you the particular cases by which it is to be supported, you must refrain from asking him if he also admits the general truth which issues from the particulars, but introduce it afterwards as a settled and admitted fact; for, in the meanwhile, he will himself come to believe that he has admitted it, and the same impression will be received by the audience, because they will remember the many questions as to the particulars, and suppose that they must, of course, have attained their end.
If the conversation turns upon some general conception which has no particular name, but requires some figurative or metaphorical designation, you must begin by choosing a metaphor that is favourable to your proposition. For instance, the names used to denote the two political parties in Spain, Serviles and Liberates, are obviously chosen by the latter. The name Protestants is chosen by themselves, and also the name Evangelicals; but the Catholics call them heretics. Similarly, in regard to the names of things which admit of a more exact and definite meaning: for example, if your opponent proposes an alteration, you can call it an innovation, as this is an invidious word. If you yourself make the proposal, it will be the converse. In the first case, you can call the antagonistic principle "the existing order," in the second, "antiquated prejudice." What an impartial man with no further purpose to serve would call "public worship" or a "system of religion," is described by an adherent as "piety," "godliness": and by an opponent as "bigotry," "superstition." This is, at bottom, a subtle petitio principii. What is sought to be proved is, first of all, inserted in the definition, whence it is then taken by mere analysis. What one man calls "placing in safe custody," another calls "throwing into prison." A speaker often betrays his purpose beforehand by the names which he gives to things. One man talks of "the clergy"; another, of "the priests."
Of all the tricks of controversy, this is the most frequent, and it is used instinctively. You hear of "religious zeal," or "fanaticism"; a "faux pas" a "piece of gallantry," or "adultery"; an "equivocal," or a "bawdy" story; "embarrassment," or "bankruptcy"; "through influence and connection," or by "bribery and nepotism"; "sincere gratitude," or "good pay."
To make your opponent accept a proposition, you must give him the counter-proposition as well, leaving him his choice of the two; and you must render the contrast as glaring as you can, so that to avoid being paradoxical he will accept the proposition, which is thus made to look quite probable. For instance, if you want to make him admit that a boy must do everything that his father tells him to do, ask him "whether in all things we must obey or disobey our parents." Or, if a thing is said to occur "often," ask whether by "often" you are to understand few or many cases; and he will say "many." It is as though you were to put grey next black, and call it white; or next white, and call it black.
This, which is an impudent trick, is played as follows: When your opponent has answered several of your questions without the answers turning out favourable to the conclusion at which you are aiming, advance the desired conclusion,—although it does not in the least follow,—as though it had been proved, and proclaim it in a tone of triumph. If your opponent is shy or stupid, and you yourself possess a great deal of impudence and a good voice, the trick may easily succeed. It is akin to the fallacy non causae ut causae.
If you have advanced a paradoxical proposition and find a difficulty in proving it, you may submit for your opponent's acceptance or rejection some true proposition, the truth of which, however, is not quite palpable, as though you wished to draw your proof from it. Should he reject it because he suspects a trick, you can obtain your triumph by showing how absurd he is; should he accept it> you have got reason on your side for the moment, and must now look about you; or else you can employ the previous trick as well, and maintain that your paradox is proved by the proposition which he has accepted. For this an extreme degree of impudence is required; but experience shows cases of it, and there are people who practise it by instinct.
Another trick is to use arguments ad hominem, or ex concessis  When your opponent makes a proposition, you must try to see whether it is not in some way—if needs be, only apparently—inconsistent with some other proposition which he has made or admitted, or with the principles of a school or sect which he has commended and approved, or with the actions of those who support the sect, or else of those who give it only an apparent and spurious support, or with his own actions or want of action. For example, should he defend suicide, you may at once exclaim, "Why don't you hang yourself?" Should he maintain that Berlin is an unpleasant place to live in, you may say, "Why don't you leave by the first train?" Some such claptrap is always possible.
[Footnote 1: The truth from which I draw my proof may he either (1) of an objective and universally valid character; in that case my proof is veracious, secundum veritatem; and it is such proof alone that has any genuine validity. Or (2) it may be valid only for the person to whom I wish to prove my proposition, and with whom I am disputing. He has, that is to say, either taken up some position once for all as a prejudice, or hastily admitted it in the course of the dispute; and on this I ground my proof. In that case, it is a proof valid only for this particular man, ad kominem. I compel my opponent to grant my proposition, but I fail to establish it as a truth of universal validity. My proof avails for my opponent alone, but for no one else. For example, if my opponent is a devotee of Kant's, and I ground my proof on some utterance of that philosopher, it is a proof which in itself is only ad hominem. If he is a Mohammedan, I may prove my point by reference to a passage in the Koran, and that is sufficient for him; but here it is only a proof ad hominem,]
If your opponent presses you with a counter-proof, you will often be able to save yourself by advancing some subtle distinction, which, it is true, had not previously occurred to you; that is, if the matter admits of a double application, or of being taken in any ambiguous sense.
If you observe that your opponent has taken up a line of argument which will end in your defeat, you must not allow him to carry it to its conclusion, but interrupt the course of the dispute in time, or break it off altogether, or lead him away from the subject, and bring him to others. In short, you must effect the trick which will be noticed later on, the mutatio controversiae. (See § xxix.)
Should your opponent expressly challenge you to produce any objection to some definite point in his argument, and you have nothing much to say, you must try to give the matter a general turn, and then talk against that. If you are called upon to say why a particular physical hypothesis cannot be accepted, you may speak of the fallibility of human knowledge, and give various illustrations of it.
When you have elicited all your premisses, and your opponent has admitted them, you must refrain from asking him for the conclusion, but draw it at once for yourself; nay, even though one or other of the premisses should be lacking, you may take it as though it too had been admitted, and draw the conclusion. This trick is an application of the fallacy non causae ut causae.
When your opponent uses a merely superficial or sophistical argument and you see through it, you can, it is true, refute it by setting forth its captious and superficial character; but it is better to meet him with a counter-argument which is just as superficial and sophistical, and so dispose of him; for it is with victory that you are concerned, and not with truth. If, for example, he adopts an argumentum ad hominem, it is sufficient to take the force out of it by a counter argumentum ad hominem or argumentum ex concessis; and, in general, instead of setting forth the true state of the case at equal length, it is shorter to take this course if it lies open to you.
If your opponent requires you to admit something from which the point in dispute will immediately follow, you must refuse to do so, declaring that it is a petitio principii For he and the audience will regard a proposition which is near akin to the point in dispute as identical with it, and in this way you deprive him of his best argument.
Contradiction and contention irritate a man into exaggerating his statement. By contradicting your opponent you may drive him into extending beyond its proper limits a statement which, at all events within those limits and in itself, is true; and when you refute this exaggerated form of it, you look as though you had also refuted his original statement. Contrarily, you must take care not to allow yourself to be misled by contradictions into exaggerating or extending a statement of your own. It will often happen that your opponent will himself directly try to extend your statement further than you meant it; here you must at once stop him, and bring him back to the limits which you set up; "That's what I said, and no more."
This trick consists in stating a false syllogism. Your opponent makes a proposition, and by false inference and distortion of his ideas you force from it other propositions which it does not contain and he does not in the least mean; nay, which are absurd or dangerous. It then looks as if his proposition gave rise to others which are inconsistent either with themselves or with some acknowledged truth, and so it appears to be indirectly refuted. This is the diversion, and it is another application of the fallacy non causae ut causae.
This is a case of the diversion by means of an instance to the contrary. With an induction ([Greek: epagogae]), a great number of particular instances are required in order to establish it as a universal proposition; but with the diversion ([Greek: apagogae]) a single instance, to which the proposition does not apply, is all that is necessary to overthrow it. This is a controversial method known as the instance—instantia, [Greek: enstasis]. For example, "all ruminants are horned" is a proposition which may be upset by the single instance of the camel. The instance is a case in which a universal truth is sought to be applied, and something is inserted in the fundamental definition of it which is not universally true, and by which it is upset. But there is room for mistake; and when this trick is employed by your opponent, you must observe (1) whether the example which he gives is really true; for there are problems of which the only true solution is that the case in point is not true—for example, many miracles, ghost stories, and so on; and (2) whether it really comes under the conception of the truth thus stated; for it may only appear to do so, and the matter is one to be settled by precise distinctions; and (3) whether it is really inconsistent with this conception; for this again may be only an apparent inconsistency.
A brilliant move is the retorsio argumenti, or turning of the tables, by which your opponent's argument is turned against himself. He declares, for instance, "So-and-so is a child, you must make allowance for him." You retort, "Just because he is a child, I must correct him; otherwise he will persist in his bad habits."
Should your opponent surprise you by becoming particularly angry at an argument, you must urge it with all the more zeal; not only because it is a good thing to make him angry, but because it may be presumed that you have here put your finger on the weak side of his case, and that just here he is more open to attack than even for the moment you perceive.
This is chiefly practicable in a dispute between scholars in the presence of the unlearned. If you have no argument ad rem, and none either ad hominem, you can make one ad auditores; that is to say, you can start some invalid objection, which, however, only an expert sees to be invalid. Now your opponent is an expert, but those who form your audience are not, and accordingly in their eyes he is defeated; particularly if the objection which you make places him in any ridiculous light. People are ready to laugh, and you have the laughers on your side. To show that your objection is an idle one, would require a long explanation on the part of your opponent, and a reference to the principles of the branch of knowledge in question, or to the elements of the matter which you are discussing; and people are not disposed to listen to it.
For example, your opponent states that in the original formation of a mountain-range the granite and other elements in its composition were, by reason of their high temperature, in a fluid or molten state; that the temperature must have amounted to some 480° Fahrenheit; and that when the mass took shape it was covered by the sea. You reply, by an argument ad auditores, that at that temperature—nay, indeed, long before it had been reached, namely, at 212° Fahrenheit—the sea would have been boiled away, and spread through the air in the form of steam. At this the audience laughs. To refute the objection, your opponent would have to show that the boiling-point depends not only on the degree of warmth, but also on the atmospheric pressure; and that as soon as about half the sea-water had gone off in the shape of steam, this pressure would be so greatly increased that the rest of it would fail to boil even at a temperature of 480°. He is debarred from giving this explanation, as it would require a treatise to demonstrate the matter to those who had no acquaintance with physics.
[Footnote 1: See § xviii.]
If you find that you are being worsted, you can make a diversion—that is, you can suddenly begin to talk of something else, as though it had a bearing on the matter in dispute, and afforded an argument against your opponent. This may be done without presumption if the diversion has, in fact, some general bearing on the matter; but it is a piece of impudence if it has nothing to do with the case, and is only brought in by way of attacking your opponent.
For example, I praised the system prevailing in China, where there is no such thing as hereditary nobility, and offices are bestowed only on those who succeed in competitive examinations. My opponent maintained that learning, as little as the privilege of birth (of which he had a high opinion) fits a man for office. We argued, and he got the worst of it. Then he made a diversion, and declared that in China all ranks were punished with the bastinado, which he connected with the immoderate indulgence in tea, and proceeded to make both of them a subject of reproach to the Chinese. To follow him into all this would have been to allow oneself to be drawn into a surrender of the victory which had already been won.
The diversion is mere impudence if it completely abandons the point in dispute, and raises, for instance, some such objection as "Yes, and you also said just now," and so on. For then the argument becomes to some extent personal; of the kind which will be treated of in the last section. Strictly speaking, it is half-way between the argumentum ad personam, which will there be discussed, and the argumentum ad hominem.
How very innate this trick is, may be seen in every quarrel between common people. If one of the parties makes some personal reproach against the other, the latter, instead of answering it by refuting it, allows it to stand,—as it were, admits it; and replies by reproaching his antagonist on some other ground. This is a stratagem like that pursued by Scipio when he attacked the Carthaginians, not in Italy, but in Africa. In war, diversions of this kind may be profitable; but in a quarrel they are poor expedients, because the reproaches remain, and those who look on hear the worst that can be said of both parties. It is a trick that should be used only faute de mieux.
This is the argumentum ad verecundiam. It consists in making an appeal to authority rather than reason, and in using such an authority as may suit the degree of knowledge possessed by your opponent.
Every man prefers belief to the exercise of judgment, says Seneca; and it is therefore an easy matter if you have an authority on your side which your opponent respects. The more limited his capacity and knowledge, the greater is the number of the authorities who weigh with him. But if his capacity and knowledge are of a high order, there are very few; indeed, hardly any at all. He may, perhaps, admit the authority of professional men versed in a science or an art or a handicraft of which he knows little or nothing; but even so he will regard it with suspicion. Contrarily, ordinary folk have a deep respect for professional men of every kind. They are unaware that a man who makes a profession of a thing loves it not for the thing itself, but for the money he makes by it; or that it is rare for a man who teaches to know his subject thoroughly; for if he studies it as he ought, he has in most cases no time left in which to teach it.
But there are very many authorities who find respect with the mob, and if you have none that is quite suitable, you can take one that appears to be so; you may quote what some said in another sense or in other circumstances. Authorities which your opponent fails to understand are those of which he generally thinks the most. The unlearned entertain a peculiar respect for a Greek or a Latin flourish. You may also, should it be necessary, not only twist your authorities, but actually falsify them, or quote something which you have invented entirely yourself. As a rule, your opponent has no books at hand, and could not use them if he had. The finest illustration of this is furnished by the French curé, who, to avoid being compelled, like other citizens, to pave the street in front of his house, quoted a saying which he described as biblical: paveant illi, ego non pavebo. That was quite enough for the municipal officers. A universal prejudice may also be used as an authority; for most people think with Aristotle that that may be said to exist which many believe. There is no opinion, however absurd, which men will not readily embrace as soon as they can be brought to the conviction that it is generally adopted. Example affects their thought just as it affects their action. They are like sheep following the bell-wether just as he leads them. They would sooner die than think. It is very curious that the universality of an opinion should have so much weight with people, as their own experience might tell them that its acceptance is an entirely thoughtless and merely imitative process. But it tells them nothing of the kind, because they possess no self-knowledge whatever. It is only the elect Who Say with Plato: [Greek: tois pollois polla dokei] which means that the public has a good many bees in its bonnet, and that it would be a long business to get at them.
But to speak seriously, the universality of an opinion is no proof, nay, it is not even a probability, that the opinion is right. Those who maintain that it is so must assume (1) that length of time deprives a universal opinion of its demonstrative force, as otherwise all the old errors which were once universally held to be true would have to be recalled; for instance, the Ptolemaic system would have to be restored, or Catholicism re-established in all Protestant countries. They must assume (2) that distance of space has the same effect; otherwise the respective universality of opinion among the adherents of Buddhism, Christianity, and Islam will put them in a difficulty.
When we come to look into the matter, so-called universal opinion is the opinion of two or three persons; and we should be persuaded of this if we could see the way in which it really arises.
We should find that it is two or three persons who, in the first instance, accepted it, or advanced and maintained it; and of whom people were so good as to believe that they had thoroughly tested it. Then a few other persons, persuaded beforehand that the first were men of the requisite capacity, also accepted the opinion. These, again, were trusted by many others, whose laziness suggested to them that it was better to believe at once, than to go through the troublesome task of testing the matter for themselves. Thus the number of these lazy and credulous adherents grew from day to day; for the opinion had no sooner obtained a fair measure of support than its further supporters attributed this to the fact that the opinion could only have obtained it by the cogency of its arguments. The remainder were then compelled to grant what was universally granted, so as not to pass for unruly persons who resisted opinions which every one accepted, or pert fellows who thought themselves cleverer than any one else.
When opinion reaches this stage, adhesion becomes a duty; and henceforward the few who are capable of forming a judgment hold their peace. Those who venture to speak are such as are entirely incapable of forming any opinions or any judgment of their own, being merely the echo of others' opinions; and, nevertheless, they defend them with all the greater zeal and intolerance. For what they hate in people who think differently is not so much the different opinions which they profess, as the presumption of wanting to form their own judgment; a presumption of which they themselves are never guilty, as they are very well aware. In short, there are very few who can think, but every man wants to have an opinion; and what remains but to take it ready-made from others, instead of forming opinions for himself?
Since this is what happens, where is the value of the opinion even of a hundred millions? It is no more established than an historical fact reported by a hundred chroniclers who can be proved to have plagiarised it from one another; the opinion in the end being traceable to a single individual.  It is all what I say, what you say, and, finally, what he says; and the whole of it is nothing but a series of assertions:
[Footnote 1: See Bayle's Pensées sur les Comètes, i., p. 10.]
Dico ego, tu dicis, sed denique dixit et ille; Dictaque post toties, nil nisi dicta vides.
Nevertheless, in a dispute with ordinary people, we may employ universal opinion as an authority. For it will generally be found that when two of them are fighting, that is the weapon which both of them choose as a means of attack. If a man of the better sort has to deal with them, it is most advisable for him to condescend to the use of this weapon too, and to select such authorities as will make an impression on his opponent's weak side. For, ex hypoihesi, he is as insensible to all rational argument as a horny-hided Siegfried, dipped in the flood of incapacity, and unable to think or judge. Before a tribunal the dispute is one between authorities alone,—such authoritative statements, I mean, as are laid down by legal experts; and here the exercise of judgment consists in discovering what law or authority applies to the case in question. There is, however, plenty of room for Dialectic; for should the case in question and the law not really fit each other, they can, if necessary, be twisted until they appear to do so, or vice versa.
If you know that you have no reply to the arguments which your opponent advances, you may, by a fine stroke of irony, declare yourself to be an incompetent judge: "What you now say passes my poor powers of comprehension; it may be all very true, but I can't understand it, and I refrain from any expression of opinion on it." In this way you insinuate to the bystanders, with whom you are in good repute, that what your opponent says is nonsense. Thus, when Kant's Kritik appeared, or, rather, when it began to make a noise in the world, many professors of the old ecclectic school declared that they failed to understand it, in the belief that their failure settled the business. But when the adherents of the new school proved to them that they were quite right, and had really failed to understand it, they were in a very bad humour.
This is a trick which may be used only when you are quite sure that the audience thinks much better of you that of your opponent. A professor, for instance may try it on a student.
Strictly, it is a case of the preceding trick: it is a particularly malicious assertion of one's own authority, instead of giving reasons. The counter-trick is to say: "I beg your pardon; but, with your penetrating intellect, it must be very easy for you to understand anything; and it can only be my poor statement of the matter that is at fault"; and then go on to rub it into him until he understands it nolens volens, and sees for himself that it was really his own fault alone. In this way you parry his attack. With the greatest politeness he wanted to insinuate that you were talking nonsense; and you, with equal courtesy, prove to him that he is a fool.
If you are confronted with an assertion, there is a short way of getting rid of it, or, at any rate, of throwing suspicion on it, by putting it into some odious category; even though the connection is only apparent, or else of a loose character. You can say, for instance, "That is Manichasism," or "It is Arianism," or "Pelagianism," or "Idealism," or "Spinozism," or "Pantheism," or "Brownianism," or "Naturalism," or "Atheism," or "Rationalism," "Spiritualism," "Mysticism," and so on. In making an objection of this kind, you take it for granted (1) that the assertion in question is identical with, or is at least contained in, the category cited—that is to say, you cry out, "Oh, I have heard that before"; and (2) that the system referred to has been entirely refuted, and does not contain a word of truth.
"That's all very well in theory, but it won't do in practice." In this sophism you admit the premisses but deny the conclusion, in contradiction with a well-known rule of logic. The assertion is based upon an impossibility: what is right in theory must work in practice; and if it does not, there is a mistake in the theory; something has been overlooked and not allowed for; and, consequently, what is wrong in practice is wrong in theory too.
When you state a question or an argument, and your opponent gives you no direct answer or reply, but evades it by a counter-question or an indirect answer, or some assertion which has no bearing on the matter, and, generally, tries to turn the subject, it is a sure sign that you have touched a weak spot, sometimes without knowing it. You have, as it were, reduced him to silence. You must, therefore, urge the point all the more, and not let your opponent evade it, even when you do not know where the weakness which you have hit upon really lies.
There is another trick which, as soon as it is practicable, makes all others unnecessary. Instead of working on your opponent's intellect by argument, work on his will by motive; and he, and also the audience if they have similar interests, will at once be won over to your opinion, even though you got it out of a lunatic asylum; for, as a general rule, half an ounce of will is more effective than a hundredweight of insight and intelligence. This, it is true, can be done only under peculiar circumstances. If you succeed in making your opponent feel that his opinion, should it prove true, will be distinctly prejudicial to his interest, he will let it drop like a hot potato, and feel that it was very imprudent to take it up.
A clergyman, for instance, is defending some philosophical dogma; you make him sensible of the fact that it is in immediate contradiction with one of the fundamental doctrines of his Church, and he abandons it.
A landed proprietor maintains that the use of machinery in agricultural operations, as practised in England, is an excellent institution, since an engine does the work of many men. You give him to understand that it will not be very long before carriages are also worked by steam, and that the value of his large stud will be greatly depreciated; and you will see what he will say.
In such cases every man feels how thoughtless it is to sanction a law unjust to himself—quam temere in nosmet legem sancimus iniquam! Nor is it otherwise if the bystanders, but not your opponent, belong to the same sect, guild, industry, club, etc., as yourself. Let his thesis be never so true, as soon as you hint that it is prejudicial to the common interests of the said society, all the bystanders will find that your opponent's arguments, however excellent they be, are weak and contemptible; and that yours, on the other hand, though they were random conjecture, are correct and to the point; you will have a chorus of loud approval on your side, and your opponent will be driven out of the field with ignominy. Nay, the bystanders will believe, as a rule, that they have agreed with you out of pure conviction. For what is not to our interest mostly seems absurd to us; our intellect being no siccum lumen. This trick might be called "taking the tree by its root"; its usual name is the argumentum ab utili.
You may also puzzle and bewilder your opponent by mere bombast; and the trick is possible, because a man generally supposes that there must be some meaning in words:
Gewöhnlich glaubt der Mensch, wenn er nur Worte hört, Es müsse sich dabei doch auch was denken lassen.
If he is secretly conscious of his own weakness, and accustomed to hear much that he does not understand, and to make as though he did, you can easily impose upon him by some serious fooling that sounds very deep or learned, and deprives him of hearing, sight, and thought; and by giving out that it is the most indisputable proof of what you assert. It is a well-known fact that in recent times some philosophers have practised this trick on the whole of the public with the most brilliant success. But since present examples are odious, we may refer to The Vicar of Wakefield for an old one.
Should your opponent be in the right, but, luckily for your contention, choose a faulty proof, you can easily manage to refute it, and then claim that you have thus refuted his whole position. This is a trick which ought to be one of the first; it is, at bottom, an expedient by which an argumentum ad hominem is put forward as an argumentum ad rem. If no accurate proof occurs to him or to the bystanders, you have won the day. For example, if a man advances the ontological argument by way of proving God's existence, you can get the best of him, for the ontological argument may easily be refuted. This is the way in which bad advocates lose a good case, by trying to justify it by an authority which does not fit it, when no fitting one occurs to them.
A last trick is to become personal, insulting, rude, as soon as you perceive that your opponent has the upper hand, and that you are going to come off worst. It consists in passing from the subject of dispute, as from a lost game, to the disputant himself, and in some way attacking his person. It may be called the argumentum ad personam, to distinguish it from the argumentum ad hominem, which passes from the objective discussion of the subject pure and simple to the statements or admissions which your opponent has made in regard to it. But in becoming personal you leave the subject altogether, and turn your attack to his person, by remarks of an offensive and spiteful character. It is an appeal from the virtues of the intellect to the virtues of the body, or to mere animalism. This is a very popular trick, because every one is able to carry it into effect; and so it is of frequent application. Now the question is, What counter-trick avails for the other party? for if he has recourse to the same rule, there will be blows, or a duel, or an action for slander.
It would be a great mistake to suppose that it is sufficient not to become personal yourself. For by showing a man quite quietly that he is wrong, and that what he says and thinks is incorrect—a process which occurs in every dialectical victory—you embitter him more than if you used some rude or insulting expression. Why is this? Because, as Hobbes observes,  all mental pleasure consists in being able to compare oneself with others to one's own advantage. Nothing is of greater moment to a man than the gratification of his vanity, and no wound is more painful than that which is inflicted on it. Hence such phrases as "Death before dishonour," and so on. The gratification of vanity arises mainly by comparison of oneself with others, in every respect, but chiefly in respect of one's intellectual powers; and so the most effective and the strongest gratification of it is to be found in controversy. Hence the embitterment of defeat, apart from any question of injustice; and hence recourse to that last weapon, that last trick, which you cannot evade by mere politeness. A cool demeanour may, however, help you here, if, as soon as your opponent becomes personal, you quietly reply, "That has no bearing on the point in dispute," and immediately bring the conversation back to it, and continue to show him that he is wrong, without taking any notice of his insults. Say, as Themistocles said to Eurybiades—Strike, but hear me. But such demeanour is not given to every one.
[Footnote 1: Elementa philosophica de Cive.]
As a sharpening of wits, controversy is often, indeed, of mutual advantage, in order to correct one's thoughts and awaken new views. But in learning and in mental power both disputants must be tolerably equal. If one of them lacks learning, he will fail to understand the other, as he is not on the same level with his antagonist. If he lacks mental power, he will be embittered, and led into dishonest tricks, and end by being rude.
The only safe rule, therefore, is that which Aristotle mentions in the last chapter of his Topica: not to dispute with the first person you meet, but only with those of your acquaintance of whom you know that they possess sufficient intelligence and self-respect not to advance absurdities; to appeal to reason and not to authority, and to listen to reason and yield to it; and, finally, to cherish truth, to be willing to accept reason even from an opponent, and to be just enough to bear being proved to be in the wrong, should truth lie with him. From this it follows that scarcely one man in a hundred is worth your disputing with him. You may let the remainder say what they please, for every one is at liberty to be a fool—desipere est jus gentium. Remember what Voltaire says: La paix vaut encore mieux que la vérité. Remember also an Arabian proverb which tells us that on the tree of silence there hangs its fruit, which is peace.