Tractatus Logico-Philosophicus · Chapter
5.132 explained
Wittgenstein argues that logical inference is justified solely by the propositions involved, not by external laws of inference.
What happens
Wittgenstein argues that logical inference is justified solely by the propositions involved, not by external laws of inference. He criticizes Frege and Russell for treating such laws as necessary, calling them senseless and superfluous.
Themes in this chapter
Logic and Tautology
The proposition critiques the need for external inference laws, emphasizing that logical relations are inherent in propositions.
Critique of Traditional Philosophy
Wittgenstein directly challenges the Frege-Russell approach to inference, deeming their laws senseless.
Characters to notice
- Mr. Wittgenstein
Author of the proposition, presenting his view on inference.
- Frege
Mentioned as one who uses laws of inference to justify conclusions.
- Bertrand Russell
Mentioned alongside Frege as employing laws of inference.
Key passages
“If p follows from q , I can conclude from q to p ; infer p from q . The method of inference is to be understood from the two propositions alone.”
If proposition p is a logical consequence of q, then I can deduce p from q. The way this inference works is entirely contained in the propositions themselves.
Clarifies Wittgenstein's view that inference is self-contained.
“Laws of inference, which—as in Frege and Russell—are to justify the conclusions, are senseless and would be superfluous.”
Rules of inference, like those used by Frege and Russell to validate conclusions, are meaningless and unnecessary.
Highlights Wittgenstein's rejection of external logical rules.