informal fallacies http://ww2.coastal.edu/dearl/phil101/fallacies.html “a short catalog of...

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  • Informal Fallacies

    http://ww2.coastal.edu/dearl/PHIL101/Fallacies.html A Short Catalog of Informal FallaciesEvaluation & Critique

  • Fallacies of PresumptionWhere premises presume what is to be provedBegging the QuestionComplex QuestionFalse Dichotomy (the EitherOr Fallacy)Suppressed Evidence

  • Begging the Question (BQ)a form of illicit reasoning wherein the illusion is produced by verbal wordplay that a conclusion has been proved. Illicit assumptionRhetorical rephrasingCircular Reasoning

  • BQ: Circular Reasoningoccurs when the truth of the conclusion rests on premises whose own truth rests on the truth of the conclusion.

    For Example:It says in the Bible that God exists. Since the Bible is Gods word, and God never speaks falsely, then everything in the Bible must be true. So, God must exist.

  • Evaluation & CritiqueIt says in the Bible that God exists. Since the Bible is Gods word, and God never speaks falsely, then everything in the Bible must be true. So, God must exist.

    What is the conclusion of this argument?So, God must exist.

  • Evaluation & CritiqueIt says in the Bible that God exists. Since the Bible is Gods word, and God never speaks falsely, then everything in the Bible must be true. So, God must exist.

    What are the premises?(1) It says in the Bible that God exists.(2) The Bible is Gods word.(3) God never speaks falsely.(4) Everything in the Bible must be true.

  • Evaluation & CritiqueThe conclusion is:So, God must exist.

    What is the offending premise, i.e., the premise or premises that presumes this conclusion?:(1) It says in the Bible that God exists.(2) The Bible is Gods word.(3) God never speaks falsely.(4) Everything in the Bible must be true.

  • Evaluation & CritiqueThe conclusion is:So, God must exist.

    The offending premise is:(3) God never speaks falsely and to a lesser extent (2) The Bible is Gods word.

    In other words, the premises assert that God exists and speaks but not falsely, and the Bible is a record of this.

  • Evaluation & CritiqueBQ: Circular Reasoning

    Definition: occurs when the truth of the conclusion rests on premises whose own truth rests on the truth of the conclusion.

    Explanation: Only existing beings can speak. If God speaks - as it says in a premise, then God is thereby presumed to exist. So the conclusion that God must exist rests on a premise which already implicitly asserts his existence.

  • BQ: Illicit Assumptionoccurs when a key premise is left unsaid, a premise whose truth is dubitable or controversial.

    For Example:Murder is morally wrong. Therefore, abortion is morally wrong.

  • Evaluation & CritiqueMurder is morally wrong. Therefore, abortion is morally wrong.

    What is the conclusion of this argument?Therefore, abortion is morally wrong.

  • Evaluation & CritiqueMurder is morally wrong. Therefore, abortion is morally wrong.

    What is the premise?(1) Murder is morally wrong.

  • Evaluation & CritiqueThe conclusion is:Therefore, abortion is morally wrong.

    What is the assumption, the unstated premise, that presumes this conclusion?:(*) Abortion is murder.

  • Evaluation & CritiqueBQ: Illicit Assumption

    Definition: occurs when a key premise is left unsaid, a premise whose truth is dubitable or controversial.

    Explanation: The arguer assumes that abortion is murder. This is precisely the statement that demands proving in order to accept the main conclusion of the argument, i.e., abortion is morally wrong.

  • Complex Questionoccurs when a questioner attempts to trap a respondent by asking a supposedly simple question which in fact contains two distinct questions.

    For Example:Where did you hide the drugs you stole?

  • Evaluation & CritiqueWhere did you hide the drugs you stole?

    What are the two questions (or statements) implicit in this one question?(1) Where did you hide the drugs? (or You hid drugs.)(2) Did you steal drugs? (or You stole drugs.)

    In other words, the very question presumes the drugs are stolen.

  • Evaluation & CritiqueBQ: Complex Question

    Definition: occurs when a questioner attempts to trap a respondent by asking a supposedly simple question which in fact contains two distinct questions.Explanation: The question is deceptively simple. It really contains two questions: (1) where are the drugs and (2) did you steal them. In fact, the question presumes the drugs are stolen.

  • False Dichotomyan illicit form of reasoning in which two alternatives (in either-or form) are presented as if their were no other alternatives when, in fact, other more palatable alternatives likely exist.

    For Example:If you dont love America then just get the hell out.

  • Evaluation & CritiqueFalse DichotomyDefinition: an illicit form of reasoning in which two alternatives (in either-or form) are presented as if their were no other alternatives when, in fact, other more palatable alternatives likely exist.

    Explanation: ???

    If you dont love America then just get the hell out.

  • Evaluation & CritiqueFalse DichotomyExplanation: The arguer suggests there are only two alternatives, love America or leave it. By love America I take this to mean do not criticize her. But it is possible to love America and to criticize her in a constructive manner.

    If you dont love America then just get the hell out.

  • Fallacies of Sensewhere the meaning either of premises or conclusions remains dubious thus clouding the overall argument structure. Equivocation Amphiboly

  • Equivocationwhere a conclusion depends on a word or set of words whose meaning is not the same as that used in the premises.quus "equal" + vocare "to call words or phrases used as if they have the same meaning in two different contexts where they do not

  • EquivocationSome have argued that its inappropriate for the press to investigate the private lives of public officials, movie stars, members of royal families, and other celebrities. However, the public has a right to know what is in the public interest, such as in cases of the governments raising taxes, its military expenditures, etc. The private lives of celebrities are also in the public interest, and since its appropriate to make known what is in the public interest, it really is appropriate for the press to investigate the private lives of celebrities.

  • Evaluation & CritiqueSome have argued that its inappropriate for the press to investigate the private lives of public officials, movie stars, members of royal families, and other celebrities. However, the public has a right to know what is in the (1) public interest, such as in cases of the governments raising taxes, its military expenditures, etc. The private lives of celebrities are also in the (2) public interest, and since its appropriate to make known what is in the public interest, it really is appropriate for the press to investigate the private lives of celebrities.

  • Evaluation & CritiqueEquivocation

    Definition: where a conclusion depends on a word or set of words whose meaning is not the same as that used in the premises.

    Explanation: The phrase public interest is used in two distinct senses. First, public interest means the goods and expenditures common to society collectively, e.g., taxes, military expenditures, etc. Second, it means the interest of private individuals about popular subjects, e.g., the interest by many in the lives of celebrities. The argument treats these two as equivalent expressions.

  • Amphibolywhere a syntactically ambiguous premise (e.g., a mistake of grammar or punctuation) leads to a false conclusion.

    For Example:A reckless motorist injured a student in his pickup truck Thursday who was jogging through campus. So kids, dont jog in pickup trucks. Its very unsafe.

  • Evaluation & CritiqueAmphiboly

    Definition: where a syntactically ambiguous premise (e.g., a mistake of grammar or punctuation) leads to a false conclusion.

    Explanation: The phrase who was jogging through campus refers to the injured student. The conclusion erroneously takes it to refer to the reckless motorist.

  • Whole Part Fallacieswhere transfer of an attribute is illegitimate from whole to part or vice versa.Composition: where an attribute of (all) the parts is erroneously asserted of the whole (i.e., a genus or a class as a whole).

    Division: where an attribute of the whole is erroneously asserted of the part(s)

  • Evaluation & CritiqueComposition or Division?

    Salt is a nonpoisonous compound. Therefore, sodium and chlorine are nonpoisonous.

    Division

  • Evaluation & CritiqueDivision

    Definition: where an attribute of the whole is erroneously asserted of the part(s) .

    Explanation: The attribute of the whole compound, i.e., that it is non-poisonous, is inferred to each element of the compound. (Each element is poisonous when isolated.)

    Salt is a nonpoisonous compound. Therefore, sodium and chlorine are nonpoisonous.

  • Evaluation & CritiqueThe CCU football team should be good next year. After all, everyone on the team is a good athlete, so the team as a whole should be good.

    CompositionDefinition: where an attribute of (all) the parts is erroneously asserted of the whole (i.e., a genus or a class as a whole).

    Explanation: ???

  • Evaluation & CritiqueThe CCU football team should be good next year. After all, everyone on the team is a good athlete, so the team as a whole should be good.

    CompositionDefinition: where

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