Fallacy

"All the fallacies of human reason had to be exhausted, before the light of a high truth could meet with ready acceptance."

"Petitio Principii is the name of an argument which assumes the conclusion that is to be proved … “the surreptitious assumption of a truth you are pretending to prove.” Since, then, the fallacy is one of assumption … its source must be found, not in what is definitely asserted, but in the world of reality or existence in which what is asserted has a definite meaning or fulfillment, that is to say, in the universe of discourse from the standpoint of which the argument is interpreted. … Whenever it exists, the fallacy directs attention to the fact that the truth of what an argument asserts depends in part upon what assumptions the argument makes; and, in view of the nature of an argument, it follows that when assumptions are put forward as reasons we necessarily fail to establish a conclusion, and fall into the merest dogmatism unless we are willing to have these assumptions called into question. … Now, when this happens, when in the course of argument assumptions take the place of reasoned judgments, the argument is fallacious because, for the reason assigned, it involves a petitio principii… When the fallacy of petitio principii is committed in a single step it is called … hysteron proteron… and when it involves more than a single step it is called circulus in probando or reasoning in a circle."

"We shouldnt decide everything by polling the masses. This is the fallacy argumentum ad numerum, the idea that something is true because great numbers believe it, as in "Eat shit. 20 trillion flies cant be wrong."

"The easiest and most popular way of practically refuting... any Fallacy is, by bringing forward a parallel case, where it leads to a manifest absurdity. A metaphysical objection may still be urged against many cases in which we thus reason from calculation of chances; an objection not likely indeed practically to influence any one, but which may afford the Sophist a triumph over those who are unable to find a solution."

"Aristotles distinction between fallacies in dictione and fallacies extra dictionem is not the same as Richard Whatelys division into logical, and non-logical or material. By "logical" fallacies Whately meant those in which "the conclusion does not follow" from the premisses; by "material," those in which the "conclusion does follow" from the premisses. In the former class, the defect of proof lies either in a manifest violation of some of the formal laws of the syllogism--quaternio terminorum, undistributed middle, illicit major, illicit minor, negative premisses, etc., defects which remain even when symbols are substituted for the terms and concepts, and which Aristotle would not regard as sophisms owing to the transparency of the mistake;--or the defect lies in a similar violation masked in ambiguous language. The transparent defects Whately called purely logical, the cloaked defects semi-logical fallacies. The latter he regarded as all alike reducible to ambiguous middle term, including in this class all Aristotles sophisms except the ignoratio elenchi, the petitio principii, and the non causa pro causa. These three he included in his "material" falacies, by which he understood mistakes due to assuming false or unproven premisses, or premisses which prove the wrong conclusion."

"Fallacies of Assumption are those errors in reasoning which occur when the assumptions on which an argument rests are not clearly distinguished from the judgments of which the argument consists. An assumption, in this connection, is anything we take for granted, but do not assert, about the subject matter of an argument. It is the equivalent of what we… speak of as the universe of discourse. Interpreted from this point of view, it is readily seen that an assumption is not an assertion, and forms no part of the asserted contents of an argument, although, as we have seen, it has a relation to the argument, a relation which is indicated with sufficient clearness by saying that it points out the sphere of reference in which what is asserted may or not be accepted. Now it is a misinterpretation of the relation between what an argument assumes and what it asserts that lies at the foundation of the fallacies that we have here to consider. Thus, when what is taken for granted or assumed is allowed to function in any part of an argument as an assertion or judgment, or when the assumption on which an argument proceeds is ambiguous, the resulting fallacy is one of assumption."

"Closely connected with the foregoing is the fallacy of the Complex Question. By a complex question, in the broadest meaning of that term, is meant one that suggests its own answer. Any question, for instance, that forces us to select, and assert in our answer to it, one of the elements of the question itself, while some other possibility is really open, is complex in the sense in which that term is here employed. If, for example, one were to ask… if your favourite colour were red or blue, or if you had given up a particular bad habit, he would be guilty of the fallacy of the complex question, if, in each case, the alternatives, as a matter of fact, were more numerous than, or were in any way different from, those stated in the question. Any leading question which complicates an issue by over simplification is fallacious for the same reason. Now, in the light of what we have said with respect to the petitio principii, it is not difficult to see that the fallacy of the complex question is occasioned by the character of the assumption on which the question rests. In the petitio principii an assumption with respect to the subject-matter of an argument functions as a premise, in the complex question it is a similar assumption that shuts out some of the material possibilities of a situation and confines an issue within too narrow limits. As in the former case, so here, the only way of meeting the difficulty is to raise the previous question, that is, to call the assumption which lies back of the fallacy into question."

"This fallacy [appeal to authority] is not in itself an error; it is impossible to learn much in today’s world without letting somebody else crunch the numbers and offer us explanations. And teachers are sources of necessary information. But how we choose our "authorities" and place a value on such information, is just another skill rarely taught in our education systems. It’s little wonder that to most folk, sound bites and talking heads are enough to count as experts. … Teaching is reinforcing the appeal to authority, where anybody who seems more intelligent than you must ultimately be right. … We educators must simply role-model critical thinking. … Educators themselves have to be prepared to show that “evidence” and “answers” are two separate things by firmly believing that, themselves."

"A number of fallacies used deliberately in attempts to urge unreasoned commitment fall under the general classification of irrelevant evidence. ...Whenever personalities, motives, insinuating remarks about reputation, personal habits, and the like are introduced... the argument will bear watching. Ad hominem, the practice of directing the argument to the man rather than to the merits of the proposal, is both ancient and popular. Argumentum ad misericordiam...direct appeal to the emotions of pity rather than to the points or merit of the case. ...Argumentum ad ignorantium is the name given to the fallacy of shifting the burden of proof... by noting that ones opponents are unable to produce positive evidence in disproof... especially disconcerting when used in connection with nonverifiable propositions involving religious or metaphysical concepts. ...It takes real courage to resist it when combined with Argumentum ad populum, an appeal to popular feelings, passion or prejudice, or with Argumentum ad verecundiam, a reference to the fact that highly respected persons, organizations, or authorities in other fields have endorsed it. All such fallacies, when used as devices for short-cutting reflection, depend for their success on ignoratio elenchi, ignorance of what constitutes refutation or substantiation of the point at issue. ...Information about correct and incorrect forms of reasoning is not enough to immunize one against clever appeals to ones emotions and prejudices."

"There is always hope of a man so long as he dwells in the region of the direct categorical proposition and the unambiguous term; so long as he does not deny the rightly drawn conclusion after accepting the major and minor premisses. This may seem a scanty virtue and very easy grace. Yet experience shows it to be too hard of attainment for those who tamper with disinterestedness of conviction, for the sake of luxuriating in the softness of spiritual transport without interruption from a syllogism."

"The specialist is one who never makes small mistakes while moving towards the grand fallacy."

"Ignoratio Elenchi, according to Aristotle, is a fallacy which arises from “ignorance of the nature of refutation.” In order to refute an assertion, Aristotle says we must prove its contradictory; the proof, consequently, of a proposition which stood in any other relation than that to the original, would be an ignoratio elenchi… Since Aristotle, the scope of the fallacy has been extended to include all cases of proving the wrong point… “I am required to prove a certain conclusion; I prove, not that, but one which is likely to be mistaken for it; in that lies the fallacy… For instance, instead of proving that ‘this person has committed an atrocious fraud,’ you prove that ‘this fraud he is accused of is atrocious;’” … The nature of the fallacy, then, consists in substituting for a certain issue another which is more or less closely related to it, and arguing the substituted issue. The fallacy does not take into account whether the arguments do or do not really support the substituted issue, it only calls attention to the fact that they do not constitute a proof of the original one… It is a particularly prevalent and subtle fallacy and it assumes a great variety of forms. But whenever it occurs and whatever form it takes, it is brought about by an assumption that leads the person guilty of it to substitute for a definite subject of inquiry another which is in close relation with it. In the [[w:petitio principii|petitio principii] the fallacy may be described as an assumption of the premises; in the complex question, as an assumption of the answer; and in the ignoratio elenchi, as an assumption of the question at issue."