more from Ian Rumfitt

Single Idea 18808

[catalogued under 5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-]

Full Idea

Our deductive practices seem to presuppose the Cut Law.

Gist of Idea

Normal deduction presupposes the Cut Law

Source

Ian Rumfitt (The Boundary Stones of Thought [2015], 2.3)

Book Reference

Rumfitt,Ian: 'The Boundary Stones of Thought' [OUP 2015], p.43


A Reaction

That is, if you don't believe that deductions can be transitive (and thus form a successful chain of implications), then you don't really believe in deduction. It remains a well known fact that you can live without the Cut Law.