8 ideas
| 10845 | To be true a sentence must express a proposition, and not be ambiguous or vague or just expressive [Lewis] |
| Full Idea: Sentences or assertions can be derivately called true, if they succeed in expressing determinate propositions. A sentence can be ambiguous or vague or paradoxical or ungrounded or not declarative or a mere expression of feeling. | |
| From: David Lewis (Forget the 'correspondence theory of truth' [2001], p.276) | |
| A reaction: Lewis has, of course, a peculiar notion of what a proposition is - it's a set of possible worlds. I, with my more psychological approach, take a proposition to be a particular sort of brain event. |
| 10847 | Truthmakers are about existential grounding, not about truth [Lewis] |
| Full Idea: Instances of the truthmaker principle are equivalent to biconditionals not about truth but about the existential grounding of all manner of other things; the flying pigs, or what-have-you. | |
| From: David Lewis (Forget the 'correspondence theory of truth' [2001]) | |
| A reaction: The question then is what the difference is between 'existential grounding' and 'truth'. There wouldn't seem to be any difference at all if the proposition in question was a simple existential claim. |
| 10846 | Truthmaker is correspondence, but without the requirement to be one-to-one [Lewis] |
| Full Idea: The truthmaker principle seems to be a version of the correspondence theory of truth, but differs mostly in denying that the correspondence of truths to facts must be one-to-one. | |
| From: David Lewis (Forget the 'correspondence theory of truth' [2001], p.277) | |
| A reaction: In other words, several different sentences might have exactly the same truthmaker. |
| 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. |
| 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). |
| 1863 | If the soul achieves well-being in another life, it doesn't follow that I do [Aquinas] |
| Full Idea: Even if soul achieves well-being in another life, that doesn't mean I do or any other human being does. | |
| From: Thomas Aquinas (Super Epistolam Pauli Apostoli [1272]) |