Fallacies & Logic Puzzles
∴Why This Matters
Logic isn't just academic—it's a defense against manipulation and a tool for puzzle-solving. This module applies everything you've learned to real-world fallacies and classic puzzles.
Formal Fallacies
Formal fallacies are structural errors—the argument form itself is invalid, regardless of content.
Affirming the Consequent
P → Q, Q ∴ P
"If it rains, the ground is wet. The ground is wet. Therefore it rained." (Could be sprinklers!)
Denying the Antecedent
P → Q, ¬P ∴ ¬Q
"If you study, you'll pass. You didn't study. Therefore you'll fail." (Could pass anyway!)
Informal Fallacies
Ad Hominem
Attacking the person, not the argument
Straw Man
Misrepresenting an argument to attack it
Appeal to Authority
Expertise doesn't transfer across fields
False Dilemma
Presenting only two options when more exist
Slippery Slope
Assuming extreme consequences without evidence
Appeal to Popularity
Popularity ≠ truth
Knights & Knaves Puzzles
?Quick Check
A says: 'I am a knave.' What is A?
✦Tip
For Knights & Knaves: Assume one answer, trace the implications, check for contradictions. If contradiction, try the other assumption.