12 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. |
21642 | If quantification is all substitutional, there is no ontology [Quine] |
Full Idea: Ontology is meaningless for a theory whose only quantification is substitutionally construed. | |
From: Willard Quine (Ontological Relativity [1968], p.64), quoted by Thomas Hofweber - Ontology and the Ambitions of Metaphysics 03.5.1 n18 | |
A reaction: Hofweber views it as none the worse for that, since clearly lots of quantification has no ontological commitment at all. But he says it is rightly called 'a nominalists attempt at a free lunch'. |
1633 | Absolute ontological questions are meaningless, because the answers are circular definitions [Quine] |
Full Idea: What makes ontological questions meaningless when taken absolutely is not universality but circularity. A question of the form "What is an F?" can only be answered with "An F is a G", which makes sense relative to the uncritical acceptance of G. | |
From: Willard Quine (Ontological Relativity [1968], p.53) |
18964 | Ontology is relative to both a background theory and a translation manual [Quine] |
Full Idea: Ontology is doubly relative. Specifying the universe of a theory makes sense only relative to some background theory, and only relative to some choice of a manual of translation of one theory into another. | |
From: Willard Quine (Ontological Relativity [1968], p.54) | |
A reaction: People tend to forget about the double nature of Quine's notion of ontological commitment, and usually only talk about the commitment of the theory being employed. Why is the philosophical community not devoting itself to the study of tranlation manuals? |
18965 | We know what things are by distinguishing them, so identity is part of ontology [Quine] |
Full Idea: We cannot know what something is without knowing how it is marked off from other things. Identity is thus of a piece with ontology. | |
From: Willard Quine (Ontological Relativity [1968], p.55) | |
A reaction: Actually it is failure of identity which seems to raise questions of individuation. If I say 'this apple is [pause] identical to this apple', I don't see how that helps me to individuate apples. |
1634 | Two things are relative - the background theory, and translating the object theory into the background theory [Quine] |
Full Idea: Relativity has two components: to the choice of a background theory, and to the choice of how to translate the object theory into the background theory. | |
From: Willard Quine (Ontological Relativity [1968], p.67) |
8470 | Reference is inscrutable, because we cannot choose between theories of numbers [Quine, by Orenstein] |
Full Idea: For Quine, we cannot sensibly ask which is the real number five, the Frege-Russell set or the Von Neumann one. There is no arithmetical or empirical way of deciding between the two. Reference is inscrutable. | |
From: report of Willard Quine (Ontological Relativity [1968]) by Alex Orenstein - W.V. Quine Ch.3 | |
A reaction: To generalise from a problem of reference in the highly abstract world of arithmetic, and say that all reference is inscrutable, strikes me as implausible. |
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). |
18963 | Indeterminacy translating 'rabbit' depends on translating individuation terms [Quine] |
Full Idea: The indeterminacy between 'rabbit', 'rabbit stage' and the rest depended only on a correlative indeterminacy of translation of the English apparatus of individuation - pronouns, plurals, identity, numerals and so on. | |
From: Willard Quine (Ontological Relativity [1968], p.35) | |
A reaction: This spells out the problem a little better than in 'Word and Object'. I just don't believe these problems are intractable. Quine is like a child endlessly asking 'why?'. |
8659 | The gods alone live forever with Shamash. The days of humans are numbered. [Anon (Gilg)] |
Full Idea: The gods alone are the ones who live forever with Shamash. / As for humans, their days are numbered. | |
From: Anon (Gilg) (The Epic of Gilgamesh [c.2300 BCE], 3.2.34), quoted by Michèle Friend - Introducing the Philosophy of Mathematics 1.2 | |
A reaction: Friend quotes this to show the antiquity of the concept of infinity. It also, of course, shows that Sumerians at that time did not believe in human immortality. |