1. Introduction to Logic Lecture 5b More Fallacies
By David Kelsey

2. Ad Hominem
To commit this fallacy is to think that some consideration about a person refutes the claims that he or she makes.
Confusing the person and the claim:

3. Ad Hominem again A personal attack ad hominem:
claiming that because someone has certain negative features it follows that a claim she makes is false.
Examples
Inconsistency ad hominem:
to hold that what someone says is false because it is inconsistent with something else she has said or done.
Examples

4. Circumstantial & Positive ad hominem
Circumstantial ad hominem:
holding that because a person’s circumstances are a certain way it follows that some claim she makes is false.
Priest example
Positive ad hominem:
holding that the claim a person makes follows from some positive consideration about the person.

5. Poisoning the Well To poison the well an in advance ad hominem.
For example,

6. Genetic Fallacy
When one tries to refute a claim based on its origin or history she has committed the genetic fallacy.
Belief in God’s existence
Genetic fallacy vs. Circumstantial ad Hominem

7. Straw Man Straw man fallacy:
trying to refute a claim or argument by distorting it or oversimplifying it or misrepresenting it in such a way that it can be easily refuted.
Reconfiguring a claim
Knocking down a straw man is easy business but knocking down a good argument is not.

8. False Dilemma False dilemma
limits considerations to a choice between only two alternatives although other reasonable alternatives are available.
The form of a false dilemma:
Using a false dilemma for the purpose of deception
Example:

9. Perfectionist fallacy
Rejecting a policy or claim because it isn’t perfect.
A kind of false dilemma
Example:

10. Line Drawing Fallacy The Line-Drawing fallacy
insisting that a conceptual line must be drawn at a particular point when drawing such a line isn’t necessary.
Examples:
Rich
Bald
Excessive force
Line drawing and Vagueness

11. Slippery Slope Slippery Slope:
Claiming that if we let some thing X occur it follows that something else Y will occur, yet there is no reason to think that if X occurs so must Y.
Causation and slippery slope arguments
Example:
Hand gun laws

12. Misplacing the Burden of Proof
Misplacing the burden of proof on the wrong side of an issue.
The 2 sides of an issue
Example:
Should we go to war with Iraq?

13. The burden of proof To say the burden of proof rests on a claim:
This just means that if one is to hold this position, then she must support it with argumentation.
Temporal Priority
Example:

14. Where does the burden lie?
Placing the burden
Plausibility:
Affirmative:

15. The burden of proof #3 Special Circumstances:
Under special circumstances the burden of proof is placed on a particular side of an issue.
The court:

16. Appeal to ignorance Appeal to ignorance
claiming that we should believe that some claim is true because no one has proved it false.
A type of burden of proof fallacy
Example:

17. Begging the Question
One begs the question when one of the premises of her argument assumes the truth of the conclusion.
Examples:
Abortion
An argument for God’s existence
Circular reasoning