Logical Fallacies Part 1 [Author unknown] Logic is pretty well understood by now, and the rules aren't all that hard. To start the ball rolling, I dragged out my old copy of Copi's _Introduction to Logic_, and turned to the section on informal fallacies. A fallacy is (in this context) a type of argument that may be psychologically persuasive, but incorrect. Obviously there are an infinite number of incorrect arguments, but there are a number of classically recognized ones that recur often. These should be recognized and arguments based on them discarded. To *very broadly* summarize Copi's list: 1. fallacies of relevance: the first set of fallacies are those in which the argument used is logically irrelevant to the conclusion. appeal to force: an argument through implied (or overt) threat. "You should agree with me because I've got a gun in my pocket". "People who believe so and so should be taken out and shot". argumentum ad hominem (abusive): argument addressed against the opponent rather than the issue, for instance making the point that one's opponent is a communist in a discussion on computer science. argumentum ad hominem (circumstantial): arguing that one's opponent, because of their circumstances, should hold a given view. For instance, arguing that a person must be against birth control because they are Catholic. argument from ignorance: the argument that something must be true simply because it hasn't been proved to be false, or vice versa. appeal to pity: appealing to pity in support of a conclusion, where the conclusion is one of fact and not of sentiment, e.g. referring to a murder suspect's dependent family. argumentum ad populum: attempting to win popular support for a conclusion by arousing emotions and enthusiasms, rather than by appeal to relevant facts. Presidential candidates hanging out at flag factories, or riding tanks, for instance. appeal to authority: citing as evidence for one's conclusion the support of someone else for that conclusion. This is valid if not conclusive if the cited authority is genuinely a studied expert in the area being discussed, but is invalid generally. accident: applying a general rule in a case where "accidental" circumstances render that inapplicable. For instance, while generally one should not exceed the speed limit, it is acceptable for emergency vehicles to do so [assuming a reasonable speed limit, of course]. converse accident/hasty generalization: generalizing by observing certain cases. For instance, considering the effect of alcohol only on those who indulge to excess, and concluding that liquor is harmful and should be outlawed. false cause: arguing that one event causes another on the basis merely that it occurs earlier, or more generally mistaking what is not the cause of something as its cause. For instance, arguing that beating of drums causes the sun to reappear after after an eclipse by citing that every time drums have been so beaten the sun has reappeared. begging the question: assuming the truth of one's proposal as a premiss for the conclusion one is trying to prove. complex question: arguing based on a response, or assumed response, to a complex or "loaded" question, where no simple yes or no response is reasonable -- "have you stopped beating your wife?" "will you vote for the Republicans and prosperity?" irrelevant conclusion: making a perfectly valid argument for a conclusion other than the one at hand. In debating a housing bill a speaker might validly argue that decent housing for all people is desirable; this is irrelevant to whether or not that particular bill will achieve that goal. 2. fallacies of ambiguity: these are arguments where certain words or phrases have ambiguous meanings that are shifted or reinterpreted in the course of the argument, rendering them fallacious. equivocation: a fallacy arising from the ambiguity or multiplicity of possible interpretations of a repeated word or phrase. "An elephant is an animal, therefore a small elephant is a small animal". amphiboly: an argument whose premisses contain statements with grammatical constructions capable of being interpreted in more than one way. Classical example: "if Croesus went to war with Cyrus, he would destroy a mighty kingdom". Based on that advice Croesus went to war with Cyrus and in so doing destroyed a mighty kingdom: his own. accent: an argument based on a change in meaning through emphasis or accent. "we should not speak ill of our friends", unaccented, may be valid, while by accenting the last word the implication is added that it may be acceptable to speak ill of others. Similarly, quoting or emphasizing something out of context ("the captain was sober today"). composition: reasoning fallaciously from the attributes of the parts of a whole to the attributes of the whole itself: "all of the parts of this machine are light, therefore the machine itself is light". Or, to infer that what may be said of a term distributively may be said of the term collectively: "a bus uses more gasoline than a car, therefore buses use more gasoline than cars". division: the reverse of composition: reasoning from the attributes of a whole to the attributes of its parts, or inferring that what may be true of a term collectively is true distributively. "HP is a very important company; I am an HP employee; therefore I am very important"; "Dogs are frequently seen in the streets; Afghan hounds are dogs; therefore Afghan hounds are frequently seen in the streets". I hope the readership at large will find this brief summary useful in analyzing invalid arguments, on their own part or that of others, and so improve the overall rational quality of the various debates. I have refrained here from referring to any specific arguments in any ongoing debates [well, there was a reference to banning alcohol, but that was Copi's example, not mine] ==================================================================== Logical Fallacies Part 2 John W. Eshleman, Ed.D. These are the basic logical fallacies, informal and formal. They are drawn from several sources. The informal fallacies are more likely to be useful, especially when you are debating with someone else. If you learn the fallacies and become fluent in them you will be able to quickly spot the use of logical fallacies in someone else's reasoning, or even your own! Note: A fallacy is a deceptive, false, or misleading argument, notion, belief, etc. The fallacies listed here are from a hypercard shareware stack that I have put together. The basic format of this list (and of the stack), is (1) the formal name of the fallacy (usually its Latin name), followed by (2) a description of the fallacy. ________________________________________________ LIST OF LOGICAL FALLACIES: ACCENTUS Description: A Fallacy of Ambiguity, where the ambiguity arises from the emphasis (accent) placed on a word or phrase. AFFIRMATION OF THE CONSEQUENT Description: An argument from the truth of a hypothetical statement, and the truth of the consequent to the truth of the antecedent. In the syllogism below, P is the antecedent and Q is the consequent: P implies Q Q is true <-- Affirming the consequent ______________ Therefore: P is true AMBIGUITY Description: An argument in the course of which at least one term is used in different senses. Also known as equivocation. There are several types of "fallacies of ambiguity," including REIFICATION, EQUIVOCATION, AMPHIBOLY, COMPOSITION, DIVISION, and ACCENTUS. AMPHIBOLY Description: A type of Fallacy of Ambiguity where the ambiguity involved is of an "amphibolous" (equivocal, uncertain) nature. Amphiboly is a syntactic error. The fallacy is caused by faulty sentence structure, and can result in a meaning not intended by the author. "The department store now has pants for men with 32 waists." (How many waists do you have? I have only one!) ARGUMENTUM AD ANTIQUITAM Description: A fallacy of asserting that something is right or good simply because it is old; that is, because "that's the way it's always been." ARGUMENTUM AD BACULUM Description: An argument that resorts to the threat of force to cause the acceptance of the conclusion. Ad baculum arguments also include threats of fear to cause acceptance (e.g., "Do this or you'll go to Hades when you die!" or "Might makes right."). ARGUMENTUM AD CRUMENAM Description: Fallacy of believing that money is a criterion of correctness; that those with more money are more likely to be right. ARGUMENTUM AD HOMINEM Description: An argument that attempts to disprove the truth of what is asserted by attacking the speaker rather than the speaker's argument. Another way of putting it: Fallacy where you attack someone's character instead of dealing with salient issues. There are two basic types of ad hominem arguments: (1) abusive, and (2) circumstantial. ARGUMENTUM AD IGNORANTIAM Description: An argument that a proposition is true because it has not been shown to be false, or vice versa. Ad ignorantium arguments are also known as "appeals to ignorance." This fallacy has two forms: 1. P is true, because it has not been proven false. 2. P is false, because it has not been proven true. ARGUMENTUM AD LAZARUM Description: A fallacy of assuming that because someone is poor he or she is sounder or more virtuous than one who is wealthier. This fallacy is the opposite of the informal fallacy "argumentum ad crumenam." ARGUMENTUM AD MISERICORDIAM Description: An argument that appeals to pity for the sake of getting a conclusion accepted. ARGUMENTUM AD NAUSEUM Description: The incorrect belief that an assertion is more likely to be true the more often it is heard. An "argumentum ad nauseum" is one that employs constant repitition in asserting a truth. ARGUMENTUM AD NOVITAM Description: A fallacy of asserting that something is more correct simply because it is new or newer than something else. Or that something is better because it is newer. This type of fallacy is the opposite of the "argumentum ad antiquitam" fallacy. ARGUMENTUM AD NUMERAM Description: A fallacy that asserts that the more people who support or believe a proposition then the more likely that that proposition is correct; it equates mass support with correctness. ARGUMENTUM AD POPULUM Description: An argument that appeals to the beliefs of the multitude (i.e., the "populace"). Another way of putting it: Speaker deals with passions of audience rather than with salient issues. This fallacy is also known as "Appeal to Tradition" Ad populum arguments often occur in (1) propaganda, (2) demagoguery, and (3) advertising. ARGUMENTUM AD VERECUNDIAM Description: An argument in which an authority is appealed to on matters outside his/her field of authority. "Ad verecundiam" also refers to a fallacy of simply resorting to appeals to authority. BEGGING THE QUESTION (CIRCULAR REASONING) Description: An argument that assumes as part of its premises the very conclusion that is supposed to be true. Another way of saying this is: Fallacy of assuming at the onset of an argument the very point you are trying to prove. The fallacy is also sometimes referred to as "Circulus in Probando." This Fallacy is also known by the Latin "PETITIO PRINCIPII". BIFURCATION Description: Also referred to as the "black and white" fallacy, bifurcation is the presentation of a situation or condition with only two alternatives, whereas in fact other alternatives exist or can exist. COMPOSITION Description: An argument in which one assumes that a whole has a property solely because its various parts have that property. Composition is a type of Fallacy of Ambiguity. CONVERTING A CONDITIONAL Description: If P then Q, therefore, if Q then P. CUM HOC ERGO PROPTER HOC Description: A fallacy of correlation that links events because they occur simultaneously; one asserts that because two events occur together they are causally related, and leaves no room for other factors that may be the cause(s) of the events. This fallacy is similar to the "post hoc" fallacy. DENIAL OF THE ANTECEDENT Description: An argument in which one infers the falsity of the consequent from the truth of a hypothetical proposition, and the falsity of its antecedent. P implies Q Not-P ____________ Therefore: Not-Q DIVISION Description: An argument in which one assumes that various parts have a property solely because the whole has that same property. Division is a type of Fallacy of Ambiguity. EQUIVOCATION Description: An argument in which an equivocal expression is used in one sense in one premise and in a different sense in another premise, or in the conclusion. Equivocal means (1) of uncertain significance; not determined, and (2) having different meanings equally possible. Equivocation is a type of Fallacy of Ambiguity. The opposite of equivocation is "unovocation," in which a word always carries the same meaning through a given context. FALLACY OF INTERROGATION Description: The question asked has a presuppostion which the answerer may wish to deny, but which he/she would be accepting if he/she gave anything that would count as an answer. Any answer to the question "Why does such-and-such happen?" presupposes that such-and-such does indeed happen. FALSE ANALOGY Description: An analogy is a partial similarity between the like features of two things or events on which a comparison can be made. A false analogy involves comparing two things that are NOT similar. Note that the two things may be similar in superficial ways, but not with respect to what is being argued. HASTY GENERALIZATION (SECUNDUM QUID) Description: An argument in which a proposition is used as a premise without attention given to some obvious condition that would affect the proposition's application. This fallacy is also known as the "hasty generalization." It is a fallacy that takes evidence from several, possibly unrepresentative, cases to a general rule; generalizing from few to many. Note the relation to statistics: Much of statistics concerns whether or not a sample is representative of a larger population. The larger the sample size, the better the representativeness. Note also that the opposite of a hasty generalization is a sweeping generalization. IGNORATIO ELENCHI Description: An argument that is supposed to prove one proposition but succeeds only in proving a different one. Ignoratio elenchi stands for "pure and simple irrelevance." ILLICIT PROCESS Description: A syllogistic argument in which a term is distributed in the conclusion, but not in the premises. One of the rules for a valid categorical syllogism is that if either term is distributed in the conclusion, then it must be distributed in the premises. There are two types of Illicit Process: Illicit Process of the Major Term and Illicit Process of the Minor Term. PLURIUM INTERROGATIONUM-MANY QUESTIONS Description: A demand for a simple answer to a complex question. NON CAUSA PRO CAUSA Description: An argument to reject a proposition because of the falsity of some other proposition that seems to be a consequence of the first, but really is not. NON-SEQUITUR Description: An argument in which the conclusion is not a necessary consequence of the premises. Another way of putting this is: A conclusion drawn from premises that provide no logical connection to it. PETITIO PRINCIPII Description: Same as "Begging the Question" The argument assumes its conclusion is true but DOES NOT SHOW it to be true. Petitio principii has two forms: 1. P is true, because P is true. 2. P is true, because A is true. And A is true because B is true. And B is true because P is true. POST HOC, ERGO PROPTER HOC Description: An argument from a premise of the form "A preceded B" to a conclusion of the form "A caused B." Simply because one event precedes another event in time does not mean that the first event is the cause of the second event. This argument resembles a fallacy known as a Hasty Generalization. QUATERNIO TERMINORUM Description: An argument of the syllogistic form in which there occur four or more terms. In a standard categorical syllogism there are only three terms: a subject, a predicate, and a middle term. RED HERRING Description: A fallacy when irrelevant material is introduced to the issue being discussed, such that everyone's attention is diverted away from the points being made, and toward a different conclusion. It is not logically valid to divert a chain of reasoning with extraneous points. REIFICATION Description: To reify something is to convert an abstract concept into a concrete thing. Reification is a Fallacy of Ambiguity. Reification is also sometimes known as a fallacy of "hypostatization". SHIFTING THE BURDEN OF PROOF Description: The burden of proof is always on the person making the assertion or proposition. Shifting the burden of proof, a special case of "argumentum ad ignorantium," is a fallacy of putting the burden of proof on the person who denies or questions the assertion being made. The source of the fallacy is the assumption that something is true unless proven otherwise. SPECIAL PLEADING Description: Special pleading is a logical fallacy wherein a double standard is employed by the person making the assertion. Special pleading typically happens when one insists upon less strict treatment for the argument he/she is making than he or she would make when evaluating someone else's arguments. STRAW MAN Description: It is a fallacy to misrepresent someone else's position for the purposes of more easily attacking it, then to knock down that misrepresented position, and then to conclude that the original position has been demolished. It is a fallacy because it fails to deal with the actual arguments that one has made. SWEEPING GENERALIZATION Description: Also known by the Latin term "DICTO SIMPLICITER", a Sweeping Generalization occurs when a general rule is applied to a particular situation in which the features of that particular situation render the rule inapplicable. A sweeping generalization is the opposite of a hasty generalization. TWO WRONGS MAKE A RIGHT (TU QUOQUE) Description: Two wrongs never add up to a right; you cannot right a wrong by applying yet another wrong. Such a fallacy is a misplaced appeal to consistency. It is a fallacy because it makes no attempt to deal with the subject under discussion. UNDISTRIBUTED MIDDLE Description: A syllogistic argument in which the middle term of a categorical syllogism is not distributed in at least one of the premises. ==================================================================== Logical Fallacies Part 3 The following list of fallacies is taken from Irving M. Copi, _Introduction_to_Logic_ (McMillan, 1978, 5th ed) Chap 3 "Informal Fallacies". Copi gives numerous examples of various fallacies, so those interested may wish to consult that work. Fallacies of Relevance 1. Argumentum ad Baculum (appeal to force). The arguer appeals to force or the threat of force to compel acceptance of the conclusion. 2. Argumentum ad Hominem (abusive). "The phrase argumentum ad hominem translates literally as 'argument directed to the man.'" The abusive variety occurs when one attacks the other person rather than the other persons argument. 3. Argumentum ad Hominem (circumstantial). In this case, one tries to convince the opponent to agree to the conclusion based on the opponents circumstances. For example (from Copi), a hunter may claim an anti-hunter must say hunting is acceptable since the anti-hunter is not a vegetarian. 4. Argumentum ad Ignoratiam (argument from ignorance). "The fallacy of argumentum ad ignorantiam is illustrated by the argument that there must be ghosts because no one has ever been able to prove that there aren't any." 5. Argumentum ad Misericordiam (appeal to pity). The arguer appeals to pity where the conclusion is a matter of reason and not one of sentiment. 6. Argumentum ad Populam. "the attempt to win popular assent to a conclusion by arousing the emotions and enthusiasms of the multitude, rather than by appeal to the relevant facts." 7. Argumentum ad Verecundiam (appeal to authority). This is especially the appeal to authority outside the field of that authority's expertise. In the field of the authority's expertise, "this method of argument is in many cases perfectly legitimate, for the reference to an admitted authority in the special field of that authority's competence may carry great weight and constitute relevant evidence. ... Although it does not prove the point, it certainly tends to support it." 8. Accident. "The fallacy of accident consists in applying a general rule to a particular case whose 'accidental' circumstances render the rule inapplicable." 9. Converse Accident (hasty generalization). Making a general rule based on a few atypical cases. 10. False Cause. This is mistaking a event to be the cause of some other event. For example, the sun rises every day after my rooster crows; therefore, my rooster causes the sun to rise. 11. Petitio Principii (begging the question). The conclusion of an argument is contained in one of the premises assumed. 12. Complex Question. This is a question of the "Have you stopped beating your wife?" variety. 13. Ignoratio Elenchi (irrelevant conclusion). An argument which supports one conclusion is made to prove a different conclusion. Copi's example is a legislator who, in discussing a housing bill, argues only that decent housing for all is desirable, rather than whether the bill in question would achieve that goal. Fallacies of Ambiguity. 1. Equivocation. Using the same word in two different senses. 2. Amphiboly. Arguing from premises which are ambiguous due to their grammatical construction. 3. Accent. Stressing a word in a sentence which thereby changes the meaning. 4. Composition. Attributing to the whole the properties of the parts. 5. Division. Attributing to the parts the properties of the whole. Copi also recommends the following: W.W. Fearnside and W.B. Holther, _Fallacy:_The_Counterfeit_of_Argument_ (Prentice-Hall, 1959); D.H. Fischer, _Historian's_Fallacies_ (Harper & Row, 1970); and C.L. Hamblin, _Fallacies_ (Methuen, 1970).i ========================================================================== Logical Fallacies Part 4 Here is a list of everyday fallacies take from Peter A. Angeles Dictionary of Philosophy-- published by Barnes and Noble, copyright 1981. Great and useful book-- I strongly recommend picking up a copy. If these are not what you want, then you don't want fallacies. fallacy, types of informal. Sometimes semi-formal or quasi-formal fallacies. The following is a list of 40 informal fallacies which is by no means eshaustive. No attempt has been made to subsume them under general categories such as Fallacies, Classification of Informal [which I will also include]. 1. Black-and-white fallacy. Arguing (a) with the use of sharp ("black-and-white") distinctions despite any factual or theoretical support for them, or (b) by classifying any middle point between the extremes ("black-and-white") as one of the extremes. Examples: "If he is an atheist then he is a decent person." "He is either a conservative or a liberal." "He must not be peace-loving, since he participated in picketing the American embassy." 2. Fallacy of argumentum ad baculum (argument from power or force.) The Latin means "an argument according to the stick." "argument by means of the rod," "argument using force." Arguing to support the acceptance of an argument by a threat, or use of force. Reasoning is replaced by force, which results in the termination of logical argumentation, and elicits other kinds of behavior (such as fear, anger, reciprocal use of force, etc.). 3. Fallacy of argumentum ad hominem (argument against the man) [a personal favorite of mine]. The Latin means "argument to the man." (a) Arguing against, or rejecting a person's views by attacking or abusing his personality, character, motives, intentions, qualifications, etc. as opposed to providing evidence why the views are incorrect. Example: "What John said should not be believed because he was a Nazi sympathizer." [Well, there goes Heidegger.] 4. Fallacy of argumentum ad ignorantiam (argument from ignorance). The Latin means "argument to ignorance." (a) Arguing that something is true because no one has proved it to be false, or (b) arguing that something is false because no one has proved it to be true. Examples: (a) Spirits exist since no one has as yet proved that there are not any. (b) Spirits do not exist since no one has as yet proved their existence. Also called the appeal to ignorance: the lack of evidence (proof) for something is us ed to support its truth. 5. Fallacy of argumentum ad misericordiam (argument to pity). Arguing by appeal to pity in order to have some point accepted. Example: "I've got to have at least a B in this course, Professor Angeles. If I don't I won't stand a chance for medical school, and this is my last semester at the university." Also called the appeal to pity. 6. Fallacy of argumentum ad personam (appeal to personal interest). Arguing by appealing to the personal likes (preferences, prejudices, predispositions, etc.) of others in order to have an argument accepted. 7. Fallacy of argumentum as populum (argument to the people). Also the appeal to the gallery, appeal to the majority, appeal to what is popular, appeal to popular prejudice, appeal to the multitude, appeal to the mob instinct [appeal to the stupid, stinking masses]. Arguing in order to arouse an emotional, popular acceptance of an idea without resorting to logical justification of the idea. An appeal is made to such things as biases, prejudices, feelings, enthusiasms, attitudes of the multitude in order to evoke assent rather than to rationally support the idea. 8. Fallacy of argumentum ad verecundiam (argument to authority or to veneration) [another of my personal favorites]. (a) appealing to authority (including customs, traditions, institutions, etc.) in order to gain acceptance of a point at issue and/or (b) appealing to the feelings of reverence or respect we have of those in authority, or who are famous. Example: "I believe that the statement 'YOu cannot legislate morality' is true, because President Eisenhower said it." 9. Fallacy of accent. Sometimes clasified as ambiguity of accent. Arguing to conclusions from undue emphasis (accent, tone) upon certain words or statements. Classified as a fallacy of ambiguity whenever this anphasis creates an ambiguity or AMPHIBOLY in the words or statements used in an argument. Example: "The queen cannot but be praised." [also "We are free iff we could have done otherwise."-- as this statement is used by incompatibilists about free-will and determinism.] 10. Fallacy of accident. Also called by its Latin name a dicto simpliciter ad dictum secundum quid. (a) Applying a general rule or principle to a particular instance whose circumstances by "accident" do not allow the proper application of that generalization. Example: "It is a general truth that no one should lie. Therefore, no one should lie if a murderer at the point of a knife asks you for information you know would lead to a further murder." (b) The error in arumentation of applying a general stat ement to a situation to which it cannot, and was not necessarily intended to, be applied. 11. Fallacy of ambiguity. An argument that has at least one ambiguous word or statement from which a misleading or wrong conclusion is drawn. 12. Fallacy of amphiboly. Arguing to conclusions from statements that themselves are amphibolous-- ambiguous because of their syntax (grammatical construction). Sometimes classified as a fallacy of ambiguity. 13. Fallacy of begging the question. (a) Arriving at a conclusion from statements that themselves are questionable and have to be proved but are assumed true. Example: The universe has a beginning. Every thing that has a beginning has a beginner. Therefore, the universe has a beginner called God. This assumes (begs the question) that the universe does indeed have a beginning and also that all things that have a beginning have a beginner. (b) Assuming the conclusion as part of the conclusion in the premises of an argument. Sometimes called circular reasoning, vicious circularity, vicious circle fallacy. Example: "Everything has a cause. The universe is a thing. Therefore, the universe is a thing that has a cause." (c) Arguing in a circle. One statement is supported by reference to another statement which is itself supported by reference to the first statement [such as a coherentist account of knowledge/truth]. Example: "Aristocracy is the best form of government because the best form of government if that which has strong aristocratic leadership." 14. Fallacy of complex question (or loaded question). (a) Asking questions for which either a yes or no answer will incriminate the respondent. The desired answer is already tacitly assumed in the question and no qualification of the simple answer is allowed. Example: "Have you discontinued the use of opiates?" (b) Asking questions that are based on unstated attitudes or questionable (or unjustified) assumptions. These questions are often asked rhetorically of the respondent in such a way as to elicit an agreement with those attitudes or assumptions from others. Example: "How long are you going to put up with this brutality?" 15. Fallacy of composition. Arguing (a) that what is true of each part of a whole is also (necessarily) true of the whole itself, or (b) what is true of some parts is also (necessarily) true of the whole itself. Example: "Each member (or some members) of the team is married, therefore the team also has (must have) a wife." [A less silly example-- you promise me that you will come to Portland tomorrow, you also promise someone else that you will go to Detroit tomorrow. Now, you ought to be in Portland tomorrow, and you ought to be in Detroit tomorrow (because you ought to keep your promises). However, it does not follow that you ought to be in both Portland and Detroit tomorrow (because ought implies can).] Inferring that a collection has a certain characteristic merely on the basis that its parts have them erroneously proceeds from regarding the collection DISTRIBUTIVELY to regarding it COLLECTIVELY. 16. Fallacy of consensus gentium. Arguing that an idea is true on the basis (a) that the majority of people believe it and/or (b) that it has been universally held by all men at all times. Example: "God exists because all cultures have had some concept of a God." 17. Fallacy of converse accident. Sometimes converse fallcy of accident. Also called by its Latin name a dicto secumdum quid ad dictum simpliciter. The error of generalizing from atypical or exceptional instances. Example: "A shot of warm brandy each night helps older people relax and sleep better. People in general ought to drink warm brandy to relieve their tension and sleep better." 18. Fallacy of division. Arguing that what is true of a whole is (a) also (necessarily) true of its parts and/or (b) also true of some of its parts. Example: "The community of Pacific Palisades is extremely wealthy. Therefore, every person living there is (must be) extremely wealthy (or therefor A man, who lives there, must be extremely wealthy." Inferring that the parts of a collection have certain characteristic merely on the basis that their collection has them erroneously proceeds from regarding t he collection collectively to regarding it distributively. 19. Fallacy of equivocation. An argument in which a word is used with one meaning in one part of the argument and with another meaning in another part. A common example: "The end of a thing is its perfection; death is the end of life; hence, death is the perfection of life." 20. Fallacy of non causa pro causa. the LAtin may be translated as "there is no cause of the sort that has been given as the cause." (a) Believing that something is the cause of an effect when in reality it is not. Example: "My incantations caused it to rain." (b) Arguing so that a statement appears unacceptable because it implies another statement that is false (but in reality does not). 21. Fallacy of post hoc ergo propter hoc. The Latin means "after this therefore the consequence (effect) of this," or "after this therefore because of this." Sometimes simply fallacy of false cause. Concluding that one thing is the cause of another thing because it precedes it in time. A confusion between the concept of succession and that of causation. Example: "A black cat ran across my path. Ten minutes later I was hit by a truck. Therefore, the cat's running across my path was the cause of my being hit by a truck." 22. Fallacy of hasy generalization. Sometimes fallacy of hasty induction. An error of reasoning whereby a general statement is asserted (inferred) based on (a) limited information or (b) inadequate evidence, or (c) an unrepresentative sampling. 23. Fallacy of ignoratio elenchi (irrelevant conclusion). An argument that is irrelevant; that argues for something other than that which is to be proved and thereby in no way refutes (or supports) the points at issue. Example: A lawyer in defending his alcoholic client who has murdered three people in a drunken spree argues that alcoholism is a terrible disease and attempts should be made to eliminate it. IGNORATIO ELENCHI is sometimes used as a general name for all fallacies that are based on irrelev ancy (such as ad baculum, ad hominem, as misericordiam, as populum, ad verecundiam, consensus gentium, etc.) 24. Fallacy of inconsistency. Arguing from inconsistent statements, or to conclusions that are inconsistent with the premises. See fallacy of tu quoque below. 25. Fallacy of irrelevant purpose. Arguing against something on the basis that it has not fulfilled its purpose (although in fact that was not its intended purpose). 26 Fallacy of 'is' to 'ought.' Arguing from premises that have only descriptive statements (is) to a conclusion that contains an ought, or a should. 27. Fallacy of limited (or false) alternatives. The error of insisting without full inquiry or evidence that the alternatives to a course of action have been exhausted and/or are mutually exclusive. 28. Fallacy of many questions. Sometimes fallacy of the false question. Asking a question for which a single and simple answer is demanded yet the question (a) requires a series of answers, and/or (b) requires answers to a host of other questions, each of which have to be answered separately. Example: "Have you left school?" 29. Fallacy of misleading context. Arguing by misrepresenting, distorting, omitting or quoting something out of context. 30. Fallacy of prejudice. Arguing from a bias or emotional identification or involvement with an idea (argument, doctrine, institution, etc.). 31. Fallacy of red herring. Ignoring criticism of an argument by changing attention to another subject. Examples: "You believe in abortion, yet you don't believe in the right-to-die-with-dignity bill before the legislature." 32. Fallacy of slanting. Deliberately omitting, deemphasizing, or overemphasizing certain points to the exclusion of others in order to hide evidence that is important and relevant to the conclusion of the argument and that should be taken into account of in an argument. 33. Fallacy of special pleading. (a) Accepting an idea or criticism when applied to an opponent's argument but rejecting it when applied to one's own argument. (b) rejecting an idea or criticism when applied to an opponent's argument but accepting it when applied to one's own. 34. Fallacy of the straw man. Presenting an opponent's position in as weak or misrepresented a version as possible so that it can be easily refuted. Example: "Darwinism is in error. It claims that we are all descendents from an apelike creature, from which we evolved according to natural selection. No evidence of such a creature has been found. No adequate and consistent explanation of natural selection has been given. Therefore, evolution according to Darwinism has not taken place." 35. Fallacy of the beard. Arguin (a) that small or minor differences do not (or cannot) make a difference, or are not (or cannot be) significant, or (b) arguing so as to find a definite point at which something can be named. For example, insisting that a few hairs lost here and there do not indicate anything about my impending baldness; or trying to determine how many hairs a person must have before he can be called bald (or not bald). 36. Fallacy of tu quoque (you also). (a) Presenting evidence that a person's actions are not consistent with that for which he is arguing. Example: "John preaches that we should be kind and loving. He doesn't practice it. I've seen him beat up his kids." (b) Showing that a person's views are inconsistent with what he previously believed and therefore (1) he is not to be trusted, and/or (2) his new view is to be rejected. Example: "Judge Egener was against marijuana legislation four years ago when he was running for office. Now he is for it. How can you trust a man who can change his mind on such an important issue? His present position is inconsistent with his earlier view and therefore it should not be accepted." (c) Sometimes related to the Fallacy of two wrongs make a right. Example: The Democrats for years used illegal wiretapping; therefore the Republicans should not be condemned for their use of illegal wiretapping. 37. Fallacy of unqualified source. Using as support in an argument a source of authority that is not qualified to provide evidence. 38. Gambler's fallacy. (a) Arguing that since, for example, a penny has fallen tails ten times in a row then it will fall heads the eleventh time or (b) arguing that since, for example, an airline has not had an accident for the past ten years, it is then soon due for an accident. The gambler's fallacy rejects the assumption in probability theory that each event is independent of its previous happening. The chances of an event happening are always the same no matter how many times that event has taken place in the past. Given those events happening over a long enough period of time then their frequency would average out to 1/2. Sometimes referred to as the Monte Carlo fallacy (a generalized form of the gambler's fallacy): The error of assuming that because something has happened less frequently than expected in the past, there is an increased chance that it will happen soon. 39. Genetic fallacy. Arguing that the origin of something is identical with that thing with that from which it originates. Example: 'Consciousness originates in neural processes. Therefore, consciousness is (nothing but) neural processes. Sometimes referred to as the nothing-but fallacy, or the REDUCTIVE FALLACY. (b) Appraising or explaining something in terms of its origin, or source, or beginnings. (c) Arguing that something is to be rejected because its origins are [unknown] and/or suspicious. 40. Pragmatic fallacy. Arguing that something is true because it has practical effects upon people: it makes them happier, easier to deal with, more moral, loyal, stable. Example: "An immortal life exists because without such a concept men would have nothing to live for. There would be no meaning or purpose in life and everyone would be immoral." 41. Pathetic fallacy. Incorrectly projecting (attributing) human emotions, feeling, intentions, thoughts, traits upon events or ojects which do not possess the capacity for such qualities. 42. Naturalist fallacy (ethics). 1. The fallacy of reducing ethical statements to factual statements, to statements about natural events. 2. The fallacy of deriving (deducing) ethical statements from nonethical statements. [is/ought fallacy]. 3. The fallacy of defining ethical terms in nonethical (descriptive, naturalistic, or factual) terms [ought/is fallacy]. Fallacy, classification of informal. Informal fallacies may be classified in a variety of ways. Three general categories: (a) Material fallacies have to do with the facts (the matter, the content) of the argument in question. Two subcategories of material fallacies are: (1) fallacies of evidence, which refer to arguments that do not provide the required factual support (ground, evidence) for their conclusions, and (2) fallacies of irrelevance (or relevance) which refer to arguments that have supporting statements that are irrelevant to the conclusion being asserted and therefore cannot establish the truth of that conclusion. (b) Linguistic fallacies have to do with defects in arguments such as ambiguity (in which careless shifts of meanings or linguistic imprecisions lead to erroneous conclusions), vagueness, incorrect use of words, lack of clarity, linguistic inconsistencies, circularities. (c) Fallacies of irrelevant emotional appeal have to do with affecting behavior (responses, attitudes). That is, arguments are presented in such a way as to appeal to one's prejudices, biases, loyalty, dedication,fear, guilt, and so on. They persuade, cajole, threaten, or confuse in order to win assent to an argument. I hope that these definitions and examples are helpful and responsive. I have found them very useful. Ben Cushman Reed Colleg