Sophistic & Logic
This stratagem is how to defend from an "ad hominem" fallacy attack. It is related to the "caricature" fallacy.
Original text
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.
Sophistic & Logic
This stratagem is not linked to sophistic or logic.
Original text
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.
Sophistic & Logic
This stratagem relies on an invalid use of the logical implication in formal logic. Admitting the premisses but denying the conclusion (T T -> F)
Original text
"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.
Sophistic & Logic
This stratagem relies on the "guilt by association" fallacy.
The "guilt by association" fallacy and this stratagem both rely on the Euler and Venn diagrams from mathematics/logic.
Original text
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 Manichaeism" 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 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 that the system referred to has been entirely refuted, and does not contain a word of truth.
Sophistic & Logic
This stratagem relies on the "appeal to emotion" fallacy.
Original text
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.
Sophistic & Logic
This stratagem relies on a original form of the "ad hominem" fallacy.
Original text
Another trick is to use arguments ad hominem, or ex concessis.14 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.
14.) The truth from which I draw my proof may be 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 hominem. 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.
Sophistic & Logic :
This stratagem relies on the "non causae ut causae" fallacy.
Original text :
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.
Sophistic & Logic
This stratagem is related to the "petitio principii" sophism, also known as circular reasonning.
Original text
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 Liberales, 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 may 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".
Sophistic & Logic
This stratagem is close to stratagem 4 - conceal your game, and is aimed at stubborn opponents. It relies on "stealth".
Original text
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.
Sophistic & Logic
This stratagem relies on "brainfucking" your opponents by making wide-reaching questions and getting unrelated arguments from them.
The sophism this stratagem is based on is known as "Post hoc ergo propter hoc", also known as false cause, coincidental correlation or correlation not causation.
Original text
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. This 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.
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.
chap. 15 of Aristotle's De Sophistici Elenchis.