9 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. |
15432 | Structural universals might serve as possible worlds [Forrest, by Lewis] |
Full Idea: Forrest proposed that structural universals should serve as ersatz possible worlds. | |
From: report of Peter Forrest (Ways Worlds Could Be [1986]) by David Lewis - Against Structural Universals 'Intro' | |
A reaction: I prefer powers to property universals. Perhaps a possible world is a maximal set of co-existing dispositions? |
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). |
22480 | Possessing the virtue of justice disposes a person to good practical rationality [Foot] |
Full Idea: If justice is a virtue it must make action good by disposing its possessor to goodness in practical rationality; the latter consisting of the right recognition of reasons, and corresponding action. | |
From: Philippa Foot (Rationality and Virtue [1994], p.174) | |
A reaction: This somewhat inverts Aristotle, who says the possessing of good practical reason is the key to acquiring the virtues. Foot suggests that possessing the virtue promotes the practical rationality. Someone can be sensible without being virtuous. |
22477 | Calling a knife or farmer or speech or root good does not involve attitudes or feelings [Foot] |
Full Idea: No one thinks that calling a knife a good knife, a farmer a good farmer, a speech a good speech, a root a good root, necessarily expresses or even involves an attitude or feeling towards it. | |
From: Philippa Foot (Rationality and Virtue [1994], p.163) | |
A reaction: This is the Aristotelian idea (which I favour) that good derives from function. In such a case it seems obvious that it has nothing to do with expressing emotions. |
22478 | The essential thing is the 'needs' of plants and animals, and their operative parts [Foot] |
Full Idea: The key notion is the concept of need, …as when we say what a plant or animal of a certain species needs to have, …and what its operative features, such roots, leaves, hearts and lungs, need to do. | |
From: Philippa Foot (Rationality and Virtue [1994], p.164) | |
A reaction: Good. That takes it away from the idea of a function, which could be possessed by an inanimate machine (even though that still entails success and failure). Strictly, we need oxygen, but the goodness resides in the lungs. |
22479 | Observing justice is necessary to humans, like hunting to wolves or dancing to bees [Foot] |
Full Idea: The teaching and observing of the rules of justice is as necessary a part of the life of human beings as hunting together in packs with a leader is a necessary part of the lives of wolves, or dancing part of the life of the dancing bee. | |
From: Philippa Foot (Rationality and Virtue [1994], p.168) | |
A reaction: So why are some men unjust? All wolves hunt, and all appropriate bees dance. A few men even thrive on injustice. |