6 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. |
| 19413 | If we know what is good or rational, our knowledge is extended, and our free will restricted [Leibniz] |
| Full Idea: The more perfect one is, the more one is determined to the good, and so is more free at the same time. ...Our power and knowledge are more extended, and our will much the more limited within the bounds of perfect reason. | |
| From: Gottfried Leibniz (Letters to Pierre Bayle [1702], 1702) | |
| A reaction: I like this idea, which seems to me to derive from Aquinas. When I choose to eat and drink each day, or agree that 7+5 is 12, I don't complain about my lack of freedom in the choices. Goodness and reason are constraints I welcome. |
| 10805 | A sentence should be recarved to reveal its content or implication relations [Yablo] |
| Full Idea: A sentence invites recarving iff it will then do better justice to the internal structure of its content and/or its implication relations. | |
| From: Stephen Yablo (Carving Content at the Joints [2002], §11) | |
| A reaction: This invites human intervention in a logical process (by choosing which recarvings to do, instead of allowing all equivalences to generate them). He seems to think we should abstract in order to reveal logical form. |
| 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). |