Single Idea 10975

[catalogued under 5. Theory of Logic / K. Features of Logics / 6. Compactness]

Full Idea

Compactness does not deny that an inference can have infinitely many premisses. It can; but classically, it is valid if and only if the conclusion follows from a finite subset of them.

Gist of Idea

Compactness does not deny that an inference can have infinitely many premisses

Source

Stephen Read (Thinking About Logic [1995], Ch.2)

Book Reference

Read,Stephen: 'Thinking About Logic' [OUP 1995], p.43