Single Idea 18277

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

Full Idea

If p follows from q, I can make an inference from q to p, deduce p from q. The nature of the inference can be gathered only from the two propositions. They are the only possible justification of the inference. 'Laws of Inference' would be superfluous.

Gist of Idea

If q implies p, that is justified by q and p, not by some 'laws' of inference

Source

Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.132)

Book Reference

Wittgenstein,Ludwig: 'Tractatus Logico-Philosophicus (Pears)', ed/tr. Pears,D. /McGuinness,B. [RKP 1961], p.39


A Reaction

That seems to imply that each inference is judged on its particulars. But logic aims to be general. There seem to be 'laws' at a more complex level in the logic.