5 ideas
| 2626 | A philosopher is outside any community of ideas [Wittgenstein] |
| Full Idea: The philosopher is not a citizen of any community of ideas; that is what makes him a philosopher. | |
| From: Ludwig Wittgenstein (Zettel [1950], 455) | |
| A reaction: A bit surprising from the man who gave us 'language games' and 'private language argument'. |
| 13832 | Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking] |
| Full Idea: Gentzen thought that his natural deduction gets at the heart of logical reasoning, and used the sequent calculus only as a convenient tool for proving his chief results. | |
| From: report of Gerhard Gentzen (Investigations into Logical Deduction [1935]) by Ian Hacking - What is Logic? §05 |
| 6569 | 'This sentence is false' sends us in a looping search for its proposition [Wittgenstein, by Fogelin] |
| Full Idea: According to Wittgenstein, 'this sentence is false' sends us off on an endless, looping search for the proposition to be evaluated. | |
| From: report of Ludwig Wittgenstein (Zettel [1950], §691) by Robert Fogelin - Walking the Tightrope of Reason Ch.2 | |
| A reaction: Fogelin quotes this as one possible strategy for dealing with the Liar Paradox. It doesn't sound like much of a solution to the paradox, merely an account of why it is so annoying. Wittgenstein's challenge is that the Cretan can't state his problem. |
| 3790 | Causes of beliefs are irrelevant to their contents [Wittgenstein] |
| Full Idea: The causes of our belief in a proposition are indeed irrelevant to the question of what we believe. | |
| From: Ludwig Wittgenstein (Zettel [1950], i.437) | |
| A reaction: This should have nipped the causal theory of knowledge in the bud before it got started. Everyone has a different cause for their belief that 'it sometimes rains'. Cause is not justification. |
| 3102 | Why don't we experience or remember going to sleep at night? [Magee] |
| Full Idea: As a child it was incomprehensible to me that I did not experience going to sleep, and never remembered it. When my sister said 'Nobody remembers that', I just thought 'How does she know?' | |
| From: Bryan Magee (Confessions of a Philosopher [1997], Ch.I) | |
| A reaction: This is actually evidence for something - that we do not have some sort of personal identity which is separate from consciousness, so that "I am conscious" would literally mean that an item has a property, which it can lose. |