8 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. |
| 6409 | The 'simple theory of types' distinguishes levels among properties [Ramsey, by Grayling] |
| Full Idea: The idea that there should be something like a distinction of levels among properties is captured in Ramsey's 'simple theory of types'. | |
| From: report of Frank P. Ramsey (works [1928]) by A.C. Grayling - Russell | |
| A reaction: I merely report this, though it is not immediately obvious how anyone would decide which 'level' a type belonged on. |
| 3212 | Beliefs are maps by which we steer [Ramsey] |
| Full Idea: Beliefs are maps by which we steer. | |
| From: Frank P. Ramsey (works [1928]), quoted by Georges Rey - Contemporary Philosophy of Mind p.259 n5 |
| 7388 | McGinn invites surrender, by saying it is hopeless trying to imagine conscious machines [Dennett on McGinn] |
| Full Idea: McGinn invites his readers to join him in surrender: It's just impossible to imagine how software could make a conscious robot. Don't even try, he says. Other philosophical experiments (involving China) "work" by dissuading readers from imagining. | |
| From: comment on Colin McGinn (The Problem of Consciousness [1991]) by Daniel C. Dennett - Consciousness Explained 14.1 | |
| A reaction: I agree with Dennett. If you don't try to imagine how robots might do it, you are also denied the right to try to imagine how brains might manage it. Admittedly this is hard, but good imagination needs study, effort, discussion, time, information... |
| 3185 | Multiple realisability rules out hidden essences and experts as the source of water- and gold-concepts [McGinn] |
| Full Idea: The multiple realisability emphasised by functionalists rules out the hidden essences (and the 'deferential' move in semantics) that one finds in the cases, for example, of "water" and "gold" emphasised by Kripke and Putnam. | |
| From: Colin McGinn (The Problem of Consciousness [1991], p.132) | |
| A reaction: Presumably if they are 'hidden', then the people to whom we 'defer' for our concepts can't actually know about the essences we are supposed to be discussing. You can mean essences without knowing them. Cf. Loch Ness Monster. |
| 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). |