---
aliases:
  - certainty
  - OC
author: '[[thoughts/Wittgenstein|Ludwig Wittgenstein]]'
category: philosophy
date: '2025-09-18'
description: late wittgenstein notes on knowledge and doubt, examining hinge propositions that sit beneath justification and make inquiry possible.
id: On Certainty
modified: 2026-06-05 15:07:56 GMT-04:00
pdf: http://thatmarcusfamily.org/philosophy/Course_Websites/Readings/Wittgenstein%20On%20Certainty.pdf
posters: '[[library/posters/on-certainty.jpg]]'
status: current
subcategory: skepticism
tags:
  - philosophy
title: Über Gewißheit (OC)
translator: P. M. S. Hacker
year: 1969
authors: '[[thoughts/Wittgenstein|Ludwig Wittgenstein]]'
created: '2025-09-18'
published: '2025-09-18'
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slug: library/On-Certainty
permalink: https://aarnphm.xyz/library/On-Certainty.md
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---
Most notes on this edition of _On Certainty_ come from P. M. S. Hacker’s translation and commentary.[^wiley-edition]

[^wiley-edition]: Hacker’s edition gives a grammatical reading of Wittgenstein’s discussion with Norman Malcolm about G. E. Moore’s essay _A Defence of Common Sense_. It differs from the earlier Anscombe and von Wright edition in its translation and commentary.

    One result is Wittgenstein’s claim that doubt works within a background of things taken for granted. A doubt that tried to suspend that whole background would also remove the practice in which the doubt has sense.

    Hacker favors terminological consistency over smooth English. For example, he translates _Sicherheit_ consistently through §§20–50.

In §20, Wittgenstein distinguishes Moore’s claim to know that an external world exists from ordinary knowledge that a planet exists. Evidence can establish the existence of Saturn within our system of inquiry. Treating the external world as one more object awaiting the same proof misunderstands the role of the claim.

In §37, Wittgenstein asks whether calling “There are physical objects” nonsense would answer either the idealist or the realist. A bare assertion and its denial can both lose their ordinary role when they are asked to settle the whole framework in which claims about objects are tested. The apparent difficulty can therefore come from how the sentence is being used.