7 ideas
| 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. |
| 10486 | If we are rebuilding our ship at sea, we should jettison some cargo [Boolos on Neurath] |
| Full Idea: If we are sailors rebuilding our ship plank by plank on the open sea, then I know of some cargo we might want to jettison. | |
| From: comment on Otto Neurath (Protocol Sentences [1932]) by George Boolos - Must We Believe in Set Theory? p.128 | |
| A reaction: This may just be an assertion of Ockham's Razor, but the interest is that the Neurath image demands internal standards of economy etc, whereas reality itself seems to be a right mess. |
| 8485 | We must always rebuild our ship on the open sea; we can't reconstruct it properly in dry-dock [Neurath] |
| Full Idea: We are like sailors who must rebuild their ship out on the open sea, never able to dismantle it in a dry-dock and reconstruct it there out of the best materials. | |
| From: Otto Neurath (Protocol Sentences [1932]), quoted by Alex Orenstein - W.V. Quine Ch.8 | |
| A reaction: This is the classic statement of the anti-foundationalist picture of knowledge. It is often quoted by Quine. A tricky issue. I have a lot of sympathy with Bonjour's rationalist foundationalism. |
| 9381 | If some inferences are needed to fix meaning, but we don't know which, they are all relevant [Fodor/Lepore, by Boghossian] |
| Full Idea: The Master Argument for linguistic holism is: Some of an expression's inferences are relevant to fixing its meaning; there is no way to distinguish the inferences that are constitutive (from Quine); so all inferences are relevant to fixing meaning. | |
| From: report of J Fodor / E Lepore (Holism: a Shopper's Guide [1993], §III) by Paul Boghossian - Analyticity Reconsidered | |
| A reaction: This would only be if you thought that the pattern of inferences is what fixes the meanings, but how can you derive inferences before you have meanings? The underlying language of thought generates the inferences? Meanings are involved! |
| 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). |