Index of Logical Criticisms

Ad Hominem

• Definition:  Attempting to credit or discredit reasoning by calling attention to the character, actions or personal circumstances of those who accept it rather than examining the reasoning itself.
• Identification: Reconstruct the ad hominem reasoning and show how it constitutes an attempt to refute the original reasoning by focusing attention on the character, actions, or personal circumstances of those who accept it.

Contradiction

• Definition:  Being logically committed to the truth of some  statement S and it's denial not-S at the same time.
• Identification:  Identify the statement and reconstruct the reasoning by which they are logically committed to both its assertion and its denial.

Deductively Invalid

• Definition:  Explicitly reasoning in such a way that premises do not deductively imply  the conclusion.  (For rationales, this normally means that an explicitly stated principle has failed to connect the reason to the conclusion.)
• Identification: Show how it is possible for the premises to be true and the conclusion false.

Exceptional Refutation

• Definition: Attempting to criticize the use of a principle by showing that it is has exceptions, but giving no reason to believe that the principle is generally unreliable or that the exceptions apply to the particular case at hand.
• Identification: Identify the principle and the alleged exceptions in the absence of reasons for thinking the exceptions cast doubt on the reliability of the principle as stated.

Equivocation

• Definition: Using a word or expression in a sense that is alien to the given context without adequate notice or justification.
• Identification:  Identify the word or expression in question and identify the two different senses that have been equivocated upon:  (1) the sense that would normally be assumed in the given context and (2) the sense that is being assigned without adequate notice or justification.

Innuendo

• Definition:  Exploiting contextual assumptions to suggest a conclusion that has been neither stated nor logically implied, and under conditions that suggest that one would be reluctant to claim it explicitly.
• Identification:  Identify the suggested conclusion, showing how, in the given context, it might be reasonably inferred despite the fact that it was neither stated nor implied.  Give reasons for doubting that it's author would claim it explicitly.

Red Herring

• Definition:  Distracting attention from an issue by confusing it with a different issue that is irrelevant or only superficially related to the one at hand.
• Identification:  Identify the issue at hand and identify the irrelevant issue being introduced.  Show why the new issue is irrelevant and why introducing the irrelevant issue has the effect of confusing the two issues, rather than simply explicitly refocusing attention on the new issue.

Straw Man

• Definition: Attempting to discredit a view (or practice) by criticizing a weak version of it or the reasoning given in support of it.
• Identification: Identify both the original view and the weak version of that view.  Show (a) why the weak version is a version of the view  and (b) why it  is weak.

Weak Comparison

• Definition: Basing a conclusion on an alleged similarity between two or more things when it is not clear that the similarity in question is (a) sufficiently strong or (b) sufficiently relevant to the context to provide adequate support for conclusion.
• Identification:  Explicitly identify the similarity in question and identify why you think it is insufficiently strong or insufficiently relevant to the context to warrant the conclusion.

Weak Distinction

• Definition Basing a conclusion on an alleged distinction between two or more things when it is not clear that the distinction in question is (a) sufficiently strong or (b) sufficiently relevant to the context to provide adequate support the conclusion.
• Identification:  Explicitly identify the distinction in question and identify why you think it is insufficiently strong or insufficiently relevant to the context to adequately support the conclusion.

Weak Reason

• Definition:  Weakness in a rationale stemming from a reason whose truth is not sufficiently evident to justify the expressed degree of confidence in the reason and/or the conclusion that it supports.
• Identification:  Identify the reason in question.  Give reasons for thinking that the degree of confidence appropriate to the reason does not justify the expressed degree of confidence in the reason or conclusion that it supports.

Weak Principle

• Definition:  Weakness in a rationale stemming from a commitment to a principle that is not sufficiently reliable to justify the expressed degree of confidence in the conclusion or reason that it supports.
• Identification:  Identify the principle in question and its apparent level of reliability.  Show why you think the author of the reasoning has too much confidence in the conclusion in light of the apparent reliability of the principle.