# 5.141 explained — Tractatus Logico-Philosophicus

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

## What happens

Wittgenstein states that if two propositions mutually imply each other, they are identical.

## Themes in this chapter

### Logic and Tautology

Mutual implication defines propositional identity within logical structure

## Character check-ins

### Mr. Wittgenstein

Author of the proposition

## Key lines

> If p follows from q and q from p then they are one and the same proposition.

If two propositions entail each other, they are identical.

_Logical equivalence entails identity_

## Links

- HTML: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters/5-141
- Book: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se
- All chapters: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters