# 5.156 explained — Tractatus Logico-Philosophicus

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

## What happens

Wittgenstein discusses probability as a generalization that arises from incomplete knowledge of a fact. He argues that probability propositions are extracts from other propositions, serving as incomplete pictures of states of affairs when certainty is lacking.

## Themes in this chapter

### Picture Theory of Language

Probability propositions are described as incomplete pictures of states of affairs, yet still complete as pictures.

## Character check-ins

### Mr. Wittgenstein

Author of the proposition; presents the analysis of probability.

## Key lines

> Probability is a generalization. It involves a general description of a propositional form.

Probability generalizes by describing the form of propositions rather than specific facts.

_Wittgenstein ties probability to the logical form of propositions._

> Only in default of certainty do we need probability.

Probability is only necessary when we lack certain knowledge.

_Highlights the epistemic role of probability._

> The probability proposition is, as it were, an extract from other propositions.

A probability statement is derived from other propositions.

_Probability is not primitive but derived from logical relations._

## Links

- HTML: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters/5-156
- Book: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se
- All chapters: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters