10 ideas
| 13831 | Logic is based on transitions between sentences [Prawitz] |
| Full Idea: I agree entirely with Dummett that the right way to answer the question 'what is logic?' is to consider transitions between sentences. | |
| From: Dag Prawitz (Gentzen's Analysis of First-Order Proofs [1974], §04) | |
| A reaction: I always protest at this point that reliance on sentences is speciesism against animals, who are thereby debarred from reasoning. See the wonderful Idea 1875 of Chrysippus. Hacking's basic suggestion seems right. Transition between thoughts. |
| 13825 | Natural deduction introduction rules may represent 'definitions' of logical connectives [Prawitz] |
| Full Idea: With Gentzen's natural deduction, we may say that the introductions represent, as it were, the 'definitions' of the logical constants. The introductions are not literally understood as 'definitions'. | |
| From: Dag Prawitz (Gentzen's Analysis of First-Order Proofs [1974], 2.2.2) | |
| A reaction: [Hacking, in 'What is Logic? §9' says Gentzen had the idea that his rules actually define the constants; not sure if Prawitz and Hacking are disagreeing] |
| 13823 | In natural deduction, inferences are atomic steps involving just one logical constant [Prawitz] |
| Full Idea: In Gentzen's natural deduction, the inferences are broken down into atomic steps in such a way that each step involves only one logical constant. The steps are the introduction or elimination of the logical constants. | |
| From: Dag Prawitz (Gentzen's Analysis of First-Order Proofs [1974], 1.1) |
| 3238 | 'Dead person' isn't a contradiction, so 'person' is somewhat vague [Williams,B] |
| Full Idea: If we say (in opposition to a physical view of identity) that when Jones dies 'Jones ceases to exist' but 'Jones' body does not cease to exist', this shouldn't be pressed too hard, because it would make 'dead person' a contradiction. | |
| From: Bernard Williams (Are Persons Bodies? [1970], p.74) | |
| A reaction: A good point, which nicely challenges the distinction between a 'human' and a 'person', but the problem case is much more the one where Jones gets advanced Alzheimer's, rather than dies. A dead body ceases as a mechanism, as well as as a personality. |
| 3239 | You can only really love a person as a token, not as a type [Williams,B] |
| Full Idea: If you love a person as a type instead of as a token (i.e. a "person", instead of a physical body) you might prefer a run-down copy of them to no person at all, but at this point our idea of loving a person begins to crack. | |
| From: Bernard Williams (Are Persons Bodies? [1970], p.81) | |
| A reaction: Very persuasive. If you love a person you can cope with them getting old. If you own an original watercolour, you can accept that it fades, but you would replace a reproduction of it if that faded. But what, then, is it that you love? |
| 7257 | All modern social systems seem to be conspiracies of the rich [More,T] |
| Full Idea: When I consider any social system that prevails in the modern world, I can't see it as anything but a conspiracy of the rich to advance their own interests under the pretext of organizing society. | |
| From: Thomas More (Utopia [1516], Bk 2) | |
| A reaction: I'm afraid this is my own view of most conservative politics. I don't deny that there is a good case to be made for the conservative view (by Burke and Scruton, for example), but the rich will always latch onto its coat-tails. Cf. Idea 122. |
| 7254 | If you try to get elected, you should be permanently barred from seeking office [More,T] |
| Full Idea: In Utopia, anyone who deliberately tries to get himself elected to a public office is permanently disqualified from holding one. | |
| From: Thomas More (Utopia [1516], Bk 2) | |
| A reaction: This echoes a thought found in Plato (Idea 2149). I've always liked this idea. Why can't we have elections were a group of the best people are invited to stand? Well, yes, it would lead to corruption... Still, the best should be pushed to the front. |
| 7255 | Only Utopians fail to see glory in warfare [More,T] |
| Full Idea: Utopians are practically the only people on earth who fail to see anything glorious in war. | |
| From: Thomas More (Utopia [1516], Bk 2) | |
| A reaction: A refreshing thought for such an early date. Whatever dubious behaviour is nowadays attributed to Thomas More, you have to admire someone who writes this during the reign of Henry VIII. |
| 7253 | In Utopia, legal euthanasia is considered honourable [More,T] |
| Full Idea: In Utopia, officially sanctioned euthanasia is regarded as an honourable death. | |
| From: Thomas More (Utopia [1516], Bk 2) | |
| A reaction: A bit surprising coming from a writer who is now a Catholic martyr and saint. |
| 7256 | In Utopia, the Supreme Being is identical with Nature [More,T] |
| Full Idea: Everyone in Utopia agrees that the Supreme Being (which they call Mythras) is identical with Nature. | |
| From: Thomas More (Utopia [1516], Bk 2) | |
| A reaction: This sounds remarkably like full-blown Spinozean pantheism, though it should be interpreted with caution. It certainly seems to show that pantheism was a possibility in the minds of late medieval religious thinkers. |