**“** The truth of tautology is certain, of propositions possible, of contradiction impossible. **”**

Ludwig Wittgenstein, *Tractatus Logico-Philosophicus* (1921). copy citation

Author | Ludwig Wittgenstein |
---|---|

Source | Tractatus Logico-Philosophicus |

Topic | truth certainty tautology |

Date | 1921 |

Language | English |

Reference | |

Note | Translated by C. K. Ogden |

Weblink | http://www.gutenberg.org/files/5740/5740-pdf.pdf |

## Context

“Tautology leaves to reality the whole infinite logical space; contradiction fills the whole logical space and leaves no point to reality. Neither of them, therefore, can in any way determine reality.

4.464 OGD [→GER | →P/M] The truth of tautology is certain, of propositions possible, of contradiction impossible.

(Certain, possible, impossible: here we have an indication of that gradation which we need in the theory of probability.)

4.465 OGD [→GER | →P/M] The logical product of a tautology and a proposition says the same as the proposition.” source

4.464 OGD [→GER | →P/M] The truth of tautology is certain, of propositions possible, of contradiction impossible.

(Certain, possible, impossible: here we have an indication of that gradation which we need in the theory of probability.)

4.465 OGD [→GER | →P/M] The logical product of a tautology and a proposition says the same as the proposition.” source