12 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. |
| 304 | Beautiful things must be different from beauty itself, but beauty itself must be present in each of them [Plato] |
| Full Idea: Are fine things different from or identical to fineness? They are different from fineness itself, but fineness itself is in a sense present in each of them. | |
| From: Plato (Euthydemus [c.379 BCE], 301a) |
| 16120 | Knowing how to achieve immortality is pointless without the knowledge how to use immortality [Plato] |
| Full Idea: If there exists the knowledge of how to make men immortal, but without the knowledge of how to use this immortality, there seems to be no value in it. | |
| From: Plato (Euthydemus [c.379 BCE], 289b) | |
| A reaction: I take this to be not a gormless utilitarianism about knowledge, but a plea for holism, that knowledge only has value as part of some larger picture. The big view is the important view. He's wrong, though. Work out the use later. |
| 12739 | If we are dreaming, it is sufficient that the events are coherent, and obey laws [Leibniz] |
| Full Idea: Skeptics may doubt the truth of things, and if it pleases them to call the things that occur to us dreams, it suffices for these dreams to be in agreement with each other, and to obey certain laws. | |
| From: Gottfried Leibniz (On Perceptions [1680], A6.4.1398), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 7 | |
| A reaction: Leibniz flirted a great deal with phenomenalism throughout the middle of his career, as charted by Garber. Descartes made similar points. It is really only Berkeley who took this idea seriously. |
| 303 | Say how many teeth the other has, then count them. If you are right, we will trust your other claims [Plato] |
| Full Idea: If each of you says how many teeth the other has, and when they are counted we find you do know, we will believe your other claims as well. | |
| From: Plato (Euthydemus [c.379 BCE], 294c) | |
| A reaction: This is the clairvoyant problem for reliabilism, if truth is delivered for no apparent reason. Useful, but hardly knowledge. HOW did you know the number of teeth? |
| 12738 | Successful prediction shows proficiency in nature [Leibniz] |
| Full Idea: He who can finally make predictions with success must be said to have become sufficiently proficient in nature. | |
| From: Gottfried Leibniz (On Perceptions [1680], A6.4.1398), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 7 | |
| A reaction: Is prediction achieved by knowledge of laws, or knowledge of essences and powers? The trouble with most laws is that they permit exceptions. 'Things fall, unless prevented' etc. |
| 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). |
| 302 | What knowledge is required to live well? [Plato] |
| Full Idea: What knowledge would enable us to live finely for the rest of our lives? | |
| From: Plato (Euthydemus [c.379 BCE], 293a) | |
| A reaction: A successful grasp of other people's points of view might lead to respect for them. Also a realisation that we are not isolated individuals. We really are all in it together. |
| 301 | Only knowledge of some sort is good [Plato] |
| Full Idea: Nothing is good except knowledge of some sort. | |
| From: Plato (Euthydemus [c.379 BCE], 292b) | |
| A reaction: I've heard it suggested that truth is the only value. This is the Socratic idea that moral goodness is a matter of successful rational judgement. Not convinced, but interesting. |
| 305 | Something which lies midway between two evils is better than either of them [Plato] |
| Full Idea: Something which is composed of two factors which are bad for different purposes and lies midway between them is better than either of the factors. | |
| From: Plato (Euthydemus [c.379 BCE], 306a) |