More Bad Reasoning and Bad Rhetoric Violence to both People and Logic

Ad Hominem Fallacies About persons instead of premises  Personal attack/favoritism  Inconsistency (incl. double standard)  Circumstantial (positive or negative)  Poisoning the well

Ad Hominem Fallacies About persons instead of premises  Personal attack/favoritism  Inconsistency (incl. double standard)  Circumstantial (positive or negative)  Poisoning the well Characteristics of the person are not irrelevant when credibility of the source is an important factor in determining whether a claim will be accepted.

Ad Hominem Fallacies About persons instead of premises  Personal attack/favoritism  Inconsistency (incl. double standard)  Circumstantial (positive or negative)  Poisoning the well Characteristics of the person are not irrelevant when credibility of the source is an important factor in determining whether a claim will be expected. Genetic Fallacy About origins of ideas instead of premises

Straw Man Substituting a weak invention for reality  A strategy of refutation  Reworks some part of a case to make it less viable  Uses exaggeration or oversimplification to distort original position  The altered version of the original is easier to refute than the original

False Dilemma Treating contraries as contradictories  Occurs when a decision must be made  Limits alternatives (to two in a dilemma)  May use straw man technique to make one alternative more attractive  May show up as “either-or” or “if-then”

False Dilemma Treating contraries as contradictories  Occurs when a decision must be made  Limits alternatives (to two in a dilemma)  May use straw man technique to make one alternative more attractive  May show up as “either-or” or “if-then”  May show up as perfectionist fallacy (If it’s not perfect, then it’s not acceptable.)

False Dilemma Treating contraries as contradictories  Occurs when a decision must be made  Limits alternatives (to two in a dilemma)  May use straw man technique to make one alternative more attractive  May show up as “either-or” or “if-then”  May show up as perfectionist fallacy (If it’s not perfect, then it’s not acceptable.)  May show up as line-drawing fallacy (demand that category lines always be clear)

Slippery Slope Misrepresenting probability and necessity  One version asserts in the manner of inductive argument that some action will inevitably (or almost certainly) lead to some improbable consequence

Slippery Slope Misrepresenting probability and necessity  One version asserts in the manner of inductive argument that some action will inevitably (or almost certainly) lead to some improbable consequence  Second version asserts in the manner of a justification or statement of principle that once committed to a course of action, it must be followed to its conclusion

Misplacing Burden of Proof Appeal to Ignorance An attempt to evade responsibility  Burden of proof: the requirement to supply support for a claim

Misplacing Burden of Proof Appeal to Ignorance An attempt to evade responsibility  Burden of proof: the requirement to supply support for a claim  Burden of proof shifts, depending on conditions (lower initial plausibility, affirmative more than negative, special circumstances such as judicial “innocent until proven guilty”)

Misplacing Burden of Proof Appeal to Ignorance An attempt to evade responsibility  Burden of proof: the requirement to supply support for a claim  Burden of proof shifts, depending on conditions (lower initial plausibility, affirmative more than negative, special circumstances such as judicial “innocent until proven guilty”)  Problem may occur unexpectedly in debate

Begging the Question Skipping over an important issue  May occur as a conclusion that restates a premise

Begging the Question Skipping over an important issue  May occur as a conclusion that restates a premise  May occur as a premise controversial on the same grounds as the conclusion

Begging the Question Skipping over an important issue  May occur as a conclusion that restates a premise  May occur as a premise controversial on the same grounds as the conclusion  May occur as a premise that presupposes the conclusion Example: We need to widen this road because there aren’t enough lanes to handle the traffic. (Begs the question of whether all that traffic should or must be on that road. Does not beg the question of how many lanes are needed.)