# 3.31 explained — Tractatus Logico-Philosophicus

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

## What happens

Wittgenstein defines an 'expression' (or symbol) as any part of a proposition that characterizes its sense, including the proposition itself. Expressions are what propositions can share, and they characterize both form and content.

## Themes in this chapter

### Logical Atomism

The focus on expressions as fundamental units that characterize sense aligns with the atomistic decomposition of propositions into their logical components.

### Picture Theory of Language

Expressions are parts of propositions that picture reality by characterizing sense through form and content.

## Character check-ins

### Mr. Wittgenstein

Author of the Tractatus, defining the concept of expression in logical analysis.

## Key lines

> Every part of a proposition which characterizes its sense I call an expression (a symbol).

Any component of a proposition that contributes to its meaning is termed an expression or symbol.

_Wittgenstein introduces a technical term for meaningful propositional parts._

> Expressions are everything⁠—essential for the sense of the proposition⁠—that propositions can have in common with one another.

Expressions encompass all elements that are necessary for a proposition's meaning and that can be shared across different propositions.

_Expressions are the common logical currency between propositions._

> An expression characterizes a form and a content.

An expression specifies both a structural pattern and the particular material that fills it.

_Dual role of expressions in determining logical form and specific content._

## Links

- HTML: https://www.betterreads.online/discover/tractatus_logico_philosophicus_se/chapters/3-31
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