Fallacies
Logic
If a then b, also written as a->b (a implies b)
You can make any one of four assertions:
- a is true. Modus Ponens. If a is true then b must be true. Works. This is called Affirming the Antecedent.
- a is false. Doesn't work. b could be true or false for other reasons. Denying the Antecedent is not valid reasoning.
- b is true. Doesn't work. b might not require a true to be true itself.Affirming the Consequent is not valid reasoning.
- b is false. Modus Tollens. If b is false then a cannot be true. This is called Denying the Consequent.
Fallacies
- Ad Hominem Attack
- Appeal to Authority
- Appeal to Emotion
- Appeal to Fear
- Appeal to the People
- Appeal to Tradition
- Arguing from Ignorance
- Begging the Question
- Composition
- Division
- Either/Or
- Equivocation
- False Analogy. Here's a good one from 9/11.
- False Cause
- Hasty Generalization
- Origin
- Perfect Solution
- Post Hoc, Ergo Propter Hoc
- Slippery Slope
- Straw Man