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. |
22293 | Hilbert said (to block paradoxes) that mathematical existence is entailed by consistency [Hilbert, by Potter] |
Full Idea: Hilbert proposed to circuvent the paradoxes by means of the doctrine (already proposed by Poincaré) that in mathematics consistency entails existence. | |
From: report of David Hilbert (On the Concept of Number [1900], p.183) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 19 'Exist' | |
A reaction: Interesting. Hilbert's idea has struck me as weird, but it makes sense if its main motive is to block the paradoxes. Roughly, the idea is 'it exists if it isn't paradoxical'. A low bar for existence (but then it is only in mathematics!). |
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). |
23169 | Democratic institutions become impossible in a fanatical democracy [Russell] |
Full Idea: Even democracy, when it becomes fanatical, as it did …in the French Revolution, ceases to be Liberal. Indeed, a fanatical belief in democracy makes democratic institutions impossible. | |
From: Bertrand Russell (Philosophy and Politics [1950], p.26) | |
A reaction: Presumably this is because the supposed 'will of the people' is continually placed in opposition to the institutions. For example, there is a problem if a referendum is held, which produces a result in conflict with the institutions. |
23170 | Liberal opinions are tentative rather than dogmatic, and are always responsive to new evidence [Russell] |
Full Idea: The essence of the Liberal outlook lies ...in how opinions are held: instead of being held dogmatically, they are held tentatively (as they are in science), and with a consciousness that new evidence may at any moment lead to their abandonment. | |
From: Bertrand Russell (Philosophy and Politics [1950], p.26) | |
A reaction: A nice assessment. Russell shows himself finally to be a Liberal. This flexible approach to opinions is what infuriates dogmatists from both the left and the right. It might be said that the basic evidence rarely changes. |
23172 | Empiricist Liberalism is the only view for someone who favours scientific evidence and happiness [Russell] |
Full Idea: Empiricist Liberalism (not incompatible with democratic socialism) is, as in Locke's time, the only philosophy that can be adopted by a man who demands some scientific evidence for beliefs, and also desires human happiness more than some party or creed. | |
From: Bertrand Russell (Philosophy and Politics [1950], p.31) | |
A reaction: I like this way of presenting liberalism. In the modern world we are sunk if we don't pay attention to experts, so we all need a critical understanding of what counts as good evidence. Tricky in a world of lying media. |
23171 | Empiricism is ethically superior, because dogmatism favours persecution and hatred [Russell] |
Full Idea: Empiricism is to be commended not only on the grounds of its greater truth, but also on ethical grounds. Dogma demands authority rather than intelligent thought; it requires persecution of heretics and unbelievers, and favours systematic hatred. | |
From: Bertrand Russell (Philosophy and Politics [1950], p.31) | |
A reaction: He links empiricism with the liberal outlook. At its best, the respect by empiricists for evidence is a sort of humility. |