# 5.4731 explained — Tractatus Logico-Philosophicus

> Chapter companion for Tractatus Logico-Philosophicus by Ludwig Wittgenstein.

## What happens

Wittgenstein argues that self-evidence, as emphasized by Russell, is unnecessary in logic because language itself prevents logical mistakes. The a priori nature of logic is grounded in the impossibility of thinking illogically.

## Themes in this chapter

### Limits of Language and Thought

The impossibility of thinking illogically demonstrates the inherent limits of thought imposed by language.

### Logic and Tautology

Logic's a priori nature is tied to the tautological structure that prevents logical error.

## Character check-ins

### Mr. Wittgenstein

Author of the Tractatus, presenting his critique of Russell's notion of self-evidence.

### Bertrand Russell

Referenced for his extensive discussion of self-evidence in logic.

## Key lines

> Self-evidence, of which Russell has said so much, can only be discard in logic by language itself preventing every logical mistake.

The concept of self-evidence that Russell emphasizes is unnecessary because language inherently prevents logical errors.

_Wittgenstein dismisses self-evidence as a redundant notion in logic._

> That logic is a priori consists in the fact that we cannot think illogically.

The a priori nature of logic is simply that illogical thinking is impossible.

_Wittgenstein grounds the a priori status of logic in the impossibility of illogical thought._

## Links

- HTML: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters/5-4731
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- All chapters: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters