H. P. Grice, "Implicature and Fallacy"

SOPHISMA -- fallacy of accent Logic A fallacy originally noticed by Aristotle, in which an argument proceeds to a conclusion by changing the syllabic accent of a word and hence causing its meaning to be changed. Such an argument is, of course, invalid. It is later expanded to cover cases in which one argues by emphasizing different parts of a sentence hence changing its meaning. It is also called the fallacy of emphasis, and usually occurs in spoken language. “The fallacy of accent is committed whenever a statement is accented in such a way as to change its meaning, and is employed in an argument.” Carney and Scheer, Fundamentals of Logic -- fallacy of accident Logic Aristotle claimed that it is a fallacy to take an accidental property to be an essential one. The most often quoted example is: “This dog is yours; this dog is a father; therefore this dog is your father.” A fallacy of accident later came to be considered erroneous reasoning from a general rule to a particular case having accidental circumstances which prevent the general rule from applying to it unless the general rule is qualified in some way. For instance, “It is a virtue to tell the truth; so I should tell John that he has cancer.” In such a characterization, a fallacy of accident is always equated with a fallacy of secundum quid, although the latter covers a wider range. “The fallacy of accident consists in applying a general rule to a particular case whose ‘accidental’ circumstances render the rule inapplicable.” Copi, Introduction to Logic -- fallacy of ambiguity Logic Also called the fallacy of clearness, or for Aristotle a sophism. Aristotle held that this kind of fallacy arises from ambiguity in words or in the sentences that contain ambiguous words. It is a fallacy if during the course of argument the meanings of the ambiguous words shift so that the conclusion is not validly established. The major forms of this kind of fallacy include the fallacy of accent, fallacy of amphiboly, fallacy of equivocation, fallacy of composition, and fallacy of division. To avoid these fallacies, we need to distinguish the meanings of the words carefully. “Fallacies of ambiguity are arguments which are incorrect or invalid because of some ambiguity in the language, for example, because a word, phrase, or statement can be understood in different ways.” Carney and Scheer, Fundamentals of Logic -- fallacy of many questions fallacy of clearness, see fallacy of ambiguity fallacy of the complex question, another name for fallacy of many questions -- For example, “Chinese is difficult. I am a Chinese, therefore I am difficult.” This fallacy is different from the fallacy of accent, for words differently accented are not strictly the same word. “In the simplest case of fallacies dependent on language the ambiguity can be traced to doublemeaning in a single word. This is the Fallacy of Equivocation.” Hamblin, Fallacies -- fallacy of composition Logic An erroneous kind of reasoning that argues that if each part of a whole has a certain property, then the whole has that property. For instance, “If each component of this car is of good quality, the car is of good quality.” The term is also used for arguments from the premise that each individual member of a collection has a certain attribute, to the conclusion that the collection has that attribute. The argument is invalid because it mistakenly assumes that the whole or collection is a simple aggregation of the parts or individual members. The converse is the fallacy of division, which argues that if a whole or collection has a certain property, then each of its parts or members has that property. For example, “The United States is rich, so each citizen of the US is rich.” This fallacy fails to realize that there is not such a transference relationship between a whole and its parts. Both the fallacy of composition and the fallacy of division are examples of the fallacy of ambiguity, for they often involve a confusion between the distributive use and the collective use of a word. -- fallacy of false cause Logic Also called the fallacy of post hoc ergo propter hoc (Latin, after this, therefore because of this). The argument reasons that of two correlated things A and B, because A is prior to B in time, A is the cause of B. For instance, “I usually drink tea after lunch; therefore, lunch is the cause of my drinking tea.” This is incorrect because it confuses succession and causation. It moves from a merely temporal sequence of events to a causal sequence. The alleged cause is not really responsible for the consequence and is not the cause at all. Hence this fallacy is also called non causa pro causa because it mistakes what is not the cause for a real cause. -- “The fallacy of composition consists in reasoning from what is true only of the parts of some whole to what is true to the whole.” Carney and Scheer, -- fallacy of hasty generation, see fallacy of secundum quid -- “Any argument in which one mistakes what is not the cause of a given effect for its real cause is a false cause fallacy.” Carney and Scheer, Fundamentals of Logic -- Fundamentals of Logic -- fallacy of converse accident, see fallacy of secundum quid fallacy of division, see fallacy of composition fallacy of emphasis, another name for fallacy of accent fallacy of equivocation Logic The simplest form of fallacy of ambiguity. An ambiguous word or statement is used more than once in the same argument, with the meaning shifting implicitly but significantly between uses. It therefore leads to a misleading or mistaken conclusion. -- fallacy of many questions Logic Also called the fallacy of the complex question. A asks B a question and demands a simple yes or no answer. But the question implies some unwarranted presupposition that needs to be answered separately. A simple yes or no answer will make B concede the unwarranted presupposition. For example, “Have you stopped beating your father?” No matter whether B answers yes or no, he concedes that he has beaten his father at some time, but that might not be true at all. “There remains lastly the fallacy of many questions. This consists in putting questions in such a form that any single answer involves more than one admission.” Joseph, An Introduction to Logic -- fallacy of scope, see scope -- fallacy of secundum quid Logic [Latin, derived from Greek para to pe, in a certain aspect] The fallacy of neglecting qualification, which trades on the mistaken idea that what is true with certain qualifications is also true without them. It is always identified with the fallacy of accident, which applies a general principle or rule without regard to the specific aspects of the circumstances of its application. Secundum quid has an additional form, which generalizes a rule from one instance that may be atypical or exceptional. In this form it is the fallacy of hasty generalization or the fallacy of converse accident, because contrary to the fallacy of accident, it moves from the particular to the general. For example, “Smith is British, and he is very cold toward other people; therefore all British people are cold.” “The fallacy of secundum quid . . . consists in using a principle or proposition without regard to the circumstances which modify its applicability in the case or kind of cases before us.” Joseph, An Introduction to Logic -- fallacy of the undistributed middle Logic One basic rule for a valid syllogistic inference is that the term common to the two premises (the middle term) must be distributed in at least one premise, that is, the premise must imply every other premise formed by replacing the original term by other terms with part of its extension. If this rule is violated, the inference commits the fallacy of the undistributed middle, and is invalid. For example, “Smith is intelligent,” and “All philosophers are intelligent,” therefore “Smith is a philosopher.” This syllogism is incorrect, because the middle term “intelligent” in both premises is a predicate of an affirmative proposition and is distributed in neither premise. “Since people may be persuaded that syllogisms with undistributed middle terms are valid when they are not, the term ‘fallacy’ is used.” Carney and Scheer, Fundamentals of Logic