Logic
What follows from what?

Logic — Common questions

Questions about Logic

Why do philosophers care about logic?

Logic provides the rules for valid reasoning that every other branch of philosophy relies on. An argument that is logically invalid proves nothing, regardless of how plausible its premises sound. The Stanford Encyclopedia covers classical logic formally.

What is the difference between valid and sound?

A valid argument is one where the conclusion must be true if the premises are true — the logic is correct. A sound argument is valid AND has true premises. See our glossary entry on validity and the guide on valid, sound and true.

What is a logical fallacy?

A fallacy is an error in reasoning that makes an argument seem stronger than it is. Common fallacies include ad hominem (attacking the person), straw man (distorting the opponent's view), and slippery slope (assuming extreme consequences without evidence). Use our Fallacy Finder to practise identifying them.