Metalogic

Beginner

Nothing here assumes you have read philosophy before. Every term is defined where it first appears, and the motivating example comes before the formalism.

Logic About LogicPlanned
The difference between reasoning inside a logic and reasoning about one
8 min
Where Validity Comes FromPlanned
Necessity, form, and topic neutrality as three candidate marks of a logical truth
10 min
What the Tortoise Said to AchillesPlanned
Lewis Carroll's regress and why a rule of inference cannot be one more premise
9 min
Laws of ThoughtPlanned
Whether logic describes how we think, and Frege's case that it cannot
9 min
Paradoxes at the FoundationsPlanned
The liar and Russell's paradox as arguments that look valid and end in contradiction
10 min
Can Logic Be Wrong?Planned
Rival logics, the quantum logic episode, and what it would take to give up a law of logic
10 min
How We Know LogicPlanned
Intuition, convention, and inference as candidate sources of logical knowledge
9 min