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. |
| 17914 | He made a molten sea, which was ten cubits across, and thirty cubits round the edge [Anon (Kings)] |
| Full Idea: And he made a molten sea, ten cubits from the one brim to the other; it was round all about, and his height was five cubits: and a line of cubits did compass it round about. | |
| From: Anon (Kings) (11: Book of Kings 1 [c.550 BCE], 7:23) | |
| A reaction: In the sixth century BCE, this appears to give 3 as the value of Pi, though perhaps it shouldn't be taken too literally! |
| 8526 | We might treat both tropes and substances as fundamental, so we can't presume it is just tropes [Daly] |
| Full Idea: Since C.B. Martin accepts both tropes and substances as fundamental, the claim that tropes are the only fundamental constituents is a further, independent claim. | |
| From: Chris Daly (Tropes [1995], §4) | |
| A reaction: A dubious mode of argument. Martin may only make the claim because he is ignorant, of facts or of language. Why are some tropes perfectly similar? Is it the result of something more fundamental? |
| 8527 | More than one trope (even identical ones!) can occupy the same location [Daly] |
| Full Idea: More than one trope can occupy the same spatio-temporal location, and it even seems possible for a pair of exactly resembling tropes to occupy the same spatio-temporal location. | |
| From: Chris Daly (Tropes [1995], §6) | |
| A reaction: This may be the strongest objection to tropes. Being disc-shaped and red would occupy the same location. Aristotle's example of mixing white with white (Idea 557) would be the second case. Individuation of these 'particulars' is the problem. |
| 8528 | If tropes are linked by the existence of concurrence, a special relation is needed to link them all [Daly] |
| Full Idea: To explain how tropes form bundles, concurrence relations are invoked. But tropes F and G and a concurrence relation C don't ensure that F stands in C to G. So trope theory needs 'instantiation' relations (special relational tropes) after all. | |
| From: Chris Daly (Tropes [1995], §7) | |
| A reaction: Campbell presents relations as 'second-order' items dependent on tropes (Idea 8525), but that seems unclear. Daly's argument resembles Russell's (which he likes), that some sort of universal is inescapable. It also resembles Bradley's regress (7966). |
| 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). |