7 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. |
17535 | Dispositionality has its own distinctive type of modality [Mumford/Anjum] |
Full Idea: We contend that dispositionality involves a non-alethic, sui generis, irreducible modality. | |
From: S.Mumford/R.Lill Anjum (Dispositional Modality [2011], 1) | |
A reaction: This is a lovely bold proposal, and seems to be supported by Werner Heisenberg, in Idea 17534. |
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). |
22439 | There are only duties if there are rights, so truth is only for those with a right to it [Constant] |
Full Idea: A duty is that on the part of one being which corresponds to the rights of another. Where there are no rights there are no duties. To tell the truth is therefore a duty, but only to the one who has the right to the truth. | |
From: Benjamin Constant (On Political Reactions [1797], p.123), quoted by Immanuel Kant - On a supposed right to lie p.28 | |
A reaction: We can't claim a right to have all questions answered truthfully (because there is a right to privacy), but we might claim a right not to be lied to (as long as we accept a refusal to answer). Kant rejected this idea. |
22440 | Unconditional truth-telling makes a society impossible [Constant] |
Full Idea: The moral principle 'it is a duty to tell the truth' would, if taken unconditionally and singly, make any society impossible. | |
From: Benjamin Constant (On Political Reactions [1797], p.124), quoted by Immanuel Kant - On a supposed right to lie p.28 | |
A reaction: He gives the well known example of the murderer at the door asking if your friend is inside. Compare everyone becoming perfectly telepathic. Our society would collapse, but a new society would learn to live with it. |