9 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'. |
| 11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
| Full Idea: If a designated conclusion follows from the premisses, but the argument involves two howlers which cancel each other out, then the moral is that the path an argument takes from premisses to conclusion does matter to its logical evaluation. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], II) | |
| A reaction: The drift of this is that our view of logic should be a little closer to the reasoning of ordinary language, and we should rely a little less on purely formal accounts. |
| 11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
| Full Idea: If 'and' and 'but' really are alike in sense, in what might that likeness consist? Some philosophers of classical logic will reply that they share a sense by virtue of sharing a truth table. | |
| From: Ian Rumfitt ("Yes" and "No" [2000]) | |
| A reaction: This is the standard view which Rumfitt sets out to challenge. |
| 11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
| Full Idea: A connective will possess the sense that it has by virtue of its competent users' finding certain rules of inference involving it to be primitively obvious. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], III) | |
| A reaction: Rumfitt cites Peacocke as endorsing this view, which characterises the logical connectives by their rules of usage rather than by their pure semantic value. |
| 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. |
| 11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |
| Full Idea: The standard view is that affirming not-A is more complex than affirming the atomic sentence A itself, with the latter determining its sense. But we could learn 'not' directly, by learning at once how to either affirm A or reject A. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], IV) | |
| A reaction: [compressed] This seems fairly anti-Fregean in spirit, because it looks at the psychology of how we learn 'not' as a way of clarifying what we mean by it, rather than just looking at its logical behaviour (and thus giving it a secondary role). |
| 295 | The good is beautiful [Plato] |
| Full Idea: The good is beautiful. | |
| From: Plato (Lysis [c.400 BCE], 216d) | |
| A reaction: also Timaeus 87c |
| 294 | People say that friendship exists only between good men [Plato] |
| Full Idea: People say that friendship exists only between good men. | |
| From: Plato (Lysis [c.400 BCE], 214d) |