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. |
15533 | We can quantify over fictions by quantifying for real over their names [Lewis] |
Full Idea: Substitutionalists simulate quantification over fictional characters by quantifying for real over fictional names. | |
From: David Lewis (Noneism or Allism? [1990], p.159) | |
A reaction: I would say that a fiction is a file of conceptual information, identified by a label. The label brings baggage with it, and there is no existence in the label. |
15534 | We could quantify over impossible objects - as bundles of properties [Lewis] |
Full Idea: We can quantify over Meinongian objects by quantifying for real over property bundles (such as the bundle of roundness and squareness). | |
From: David Lewis (Noneism or Allism? [1990], p.159) |
15532 | 'Allists' embrace the existence of all controversial entities; 'noneists' reject all but the obvious ones [Lewis] |
Full Idea: An expansive friend of the controversial entities who says they all exist may be called an 'allist'; a tough desert-dweller who says that none of them exist may be called a 'noneist'. | |
From: David Lewis (Noneism or Allism? [1990], p.152) | |
A reaction: Lewis gives examples of the obvious and the controversial entities. Lewis implies that he himself is in between. The word 'desert' is a reference to Quine. |
15535 | We can't accept a use of 'existence' that says only some of the things there are actually exist [Lewis] |
Full Idea: If 'existence' is understood so that it can be a substantive thesis that only some of the things there are exist, we will have none of it. | |
From: David Lewis (Noneism or Allism? [1990], p.163) | |
A reaction: Lewis is a strong advocate, following Quine, of the univocal sense of the word 'exist', and I agree with them. |
4442 | Most thinkers now reject self-predication (whiteness is NOT white) so there is no Third Man problem [Armstrong] |
Full Idea: Modern upholders of universals generally reject self-predication; humanity is not a man, whiteness is not a white thing. This means that the Third Man argument does not constitute a difficulty. | |
From: David M. Armstrong (Universals and Particulars [1995], p.506) | |
A reaction: This certainly seems right, and is relevant to the modern problem of the content of thought. The idea of a tree does not need to be tree-like. |
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). |