Fallacies in Logic
Professor Cappell
Sources:
Encyclopedia of Philosophy. Vol. 5 "Logical Terms".
Asking the Right Questions: A Guide to Critical Thinking. 4th ed. Browne, M., and Keeley, S. NY: Prentice Hall.
 

1. accentus: fallacy of ambiguity due to an emphasis on word or phrase.
2. affirmation of the consequent: an argument from the truth of a hypothetical statement and the truth of the consequent to
    the truth of the antecedent.
3. ambiguity: an argument in the course of which at least one term is used in different senses. (called equivocation in Browne
    & Keeley)
4. amphiboly: ambiguity is of amphibolous nature (having a grammatical structure that allows of two interpretations.)
5. argumentum ad baculum: argument that resorts to the threat of force to cause acceptance.
6. argumentum ad hominem: an argument that attempts to disprove the truth of what is asserted by attacking the asserter or
    attempts to prove the truth of what is asserted by appealing to the opponent's special circumstances. (also called "name
    calling" in Browne and Keeley)
7. argumentum ad ignorantiam: an argument that a proposition is true because it has not been shown to be false, or vice
    versa.
8. argumentum ad misericordiam: an argument that appeals to pity for the sake of getting a conclusion accepted.
9. argumentum ad populum: an argument that appeals to the beliefs of the multitude.
10. argumentum ad verecundiam: an argument in which an authority is appealed to on matters outside his field of authority.
     (close to Browne & Keeley's "appeal to authority")
11. begging the question (circular reasoning): an argument that assumes as part of the premises the conclusion that is
      supposed to be proved. (also close to Browne & Keeley's discussion of "confusing what 'should be' with 'what is'")
12. composition: an argument in which one assumes that a whole has a property solely because its various parts have that
      property.
13. denial of the antecedent: an argument in which one infers the falsity of the consequent from the truth of a hypothetical
      proposition and the falsity of its antecedent.
14. division: an argument in which one assumes that various parts have a property solely because the whole has that property. 15. equivocation: an argument in which an equivocal expression is used in one sense in one promise and in a different sense in
      another premise or in the conclusion.
16. ignoratio elenchi: an argument that is supposed to prove one proposition but succeeds only in proving a different one.
     (close to Browne & Keeley's discussion of "red herrings")
17. illicit process: a syllogistic argument in which a term is distributed in the conclusion but not in the premises.
18. many questions: a demand for a simple answer to a complex question. (Browne & Keeley give more specific names to
      this fallacy: "false dilema", "either-or", "over-simplification", and "dichotomous thinking")
19. non causa pro causa: 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. (Close to what Bowne & Keeley call argument by "extension")
20. non sequitur: an argument in which the conclusion is not a necessary consequence of the premises.
21. post hoc, ergo propter hoc: an argument from a premise of the "A preceded B" to a conclusion of the form "A caused B". 22. quaterrnio terminorum: an argument of the syllogistic form in which there occur four or more terms.
23. secundum quid: 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. (Relevant to Browne & Keeley's discussion of identifying and
      evaluating the unstated assumptions of an argument)
24. undistributed middle: a syllogistic argument in which the middle term is not distributed in at least one of the premises.