14 ideas
| 16000 | Fixed ideas should be tackled aggressively [Kierkegaard] |
| Full Idea: Fixed ideas are like a cramp in your foot: the best remedy is to stomp on them. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], JP-III, 635) | |
| A reaction: Sound philosophical advice at any time. [SY] Does this apply in seminars, as well as in private meditation? [PG] |
| 16012 | Philosophy can't be unbiased if it ignores language, as that is no more independent than individuals are [Kierkegaard] |
| Full Idea: If the claim of philosophers to be unbiased were all it pretends to be, it would have to take account of language and its significance...Language is partly given and partly develops freely. As individuals cannot be truly independent, so too with language. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], 1840.07.18) | |
| A reaction: A surprisingly prophetic entry from Kierkegaard anticipating the linguistic turn. [SY] |
| 11022 | Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read] |
| Full Idea: Gentzen introduced a natural deduction calculus (NK) in 1934. | |
| From: report of Gerhard Gentzen (works [1938]) by Stephen Read - Thinking About Logic Ch.8 |
| 11065 | The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna] |
| Full Idea: Gentzen argued that the inferential role of a logical constant constitutes its meaning. | |
| From: report of Gerhard Gentzen (works [1938]) by Robert Hanna - Rationality and Logic 5.3 | |
| A reaction: Possibly inspired by Wittgenstein's theory of meaning as use? This idea was the target of Prior's famous connective 'tonk', which has the role of implying anything you like, proving sentences which are not logical consequences. |
| 11023 | The logical connectives are 'defined' by their introduction rules [Gentzen] |
| Full Idea: The introduction rules represent, as it were, the 'definitions' of the symbols concerned, and the elimination rules are no more, in the final analysis, than the consequences of these definitions. | |
| From: Gerhard Gentzen (works [1938]), quoted by Stephen Read - Thinking About Logic Ch.8 | |
| A reaction: If an introduction-rule (or a truth table) were taken as fixed and beyond dispute, then it would have the status of a definition, since there would be nothing else to appeal to. So is there anything else to appeal to here? |
| 11213 | Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen] |
| Full Idea: To every logical symbol there belongs precisely one inference figure which 'introduces' the symbol ..and one which 'eliminates' it. The introductions represent the 'definitions' of the symbols concerned, and eliminations are consequences of these. | |
| From: Gerhard Gentzen (works [1938], II.5.13), quoted by Ian Rumfitt - "Yes" and "No" III | |
| A reaction: [1935 paper] This passage is famous, in laying down the basics of natural deduction systems of logic (ones using only rules, and avoiding axioms). Rumfitt questions whether Gentzen's account gives the sense of the connectives. |
| 10067 | Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave] |
| Full Idea: Gentzen proved the consistency of arithmetic from assumptions which transcend arithmetic. | |
| From: report of Gerhard Gentzen (works [1938]) by Alan Musgrave - Logicism Revisited §5 | |
| A reaction: This does not contradict Gödel's famous result, but reinforces it. The interesting question is what assumptions Gentzen felt he had to make. |
| 16003 | If people marry just because they are lonely, that is self-love, not love [Kierkegaard] |
| Full Idea: People despair about being lonely and therefore get married. But is this love? I should say it is self-love. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], JP-III, 40-41) | |
| A reaction: If you decide to marry someone because you don't want to be an old maid/bachelor in your elder years, try to actually love the person you're marrying. Not just for money or sex. [SY] |
| 21910 | Our destiny is the highest pitch of world-weariness [Kierkegaard] |
| Full Idea: Our destiny in this life is to be brought to the highest pitch of world-weariness. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], 1855.09.25), quoted by Alastair Hannay - Kierkegaard 10 | |
| A reaction: The beginning of his last entry. Hardly a great general truth, but interesting. Should we aspire to exhaust life? |
| 16001 | Life may be understood backwards, but it has to be lived forwards [Kierkegaard] |
| Full Idea: Philosophy is perfectly right in saying that life must be understood backwards. But then it forgets the other side - that it must be lived forwards. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], JP-III, 635) | |
| A reaction: Some of the best philosophers dwell too much on philosophy, history and the past, while forgetting to actually live and enjoy their lives. [SY] |
| 16008 | The best way to be a Christian is without 'Christianity' [Kierkegaard] |
| Full Idea: One best becomes a Christian - without 'Christianity'. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], JP-1:214) | |
| A reaction: A very healthy attitude for followers of Jesus, given today's television evangelists, religious fundamentalist and zealots. [SY] |
| 20735 | We need to see that Christianity cannot be understood [Kierkegaard] |
| Full Idea: The problem is not to understand Christianity, but to understand that it cannot be understood. | |
| From: Søren Kierkegaard (The Journals of Kierkegaard [1850], p.146), quoted by Kevin Aho - Existentialism: an introduction 1 'Roots' | |
| A reaction: This seems to cut us intellectually adrift. We could say the same of supporting Real Madrid. There has to be some magnetism which holds our attention, and there must be something to say about that. |
| 16713 | Philosophers are the forefathers of heretics [Tertullian] |
| Full Idea: Philosophers are the forefathers of heretics. | |
| From: Tertullian (works [c.200]), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 20.2 |
| 6610 | I believe because it is absurd [Tertullian] |
| Full Idea: I believe because it is absurd ('Credo quia absurdum est'). | |
| From: Tertullian (works [c.200]), quoted by Robert Fogelin - Walking the Tightrope of Reason n4.2 | |
| A reaction: This seems to be a rather desperate remark, in response to what must have been rather good hostile arguments. No one would abandon the support of reason if it was easy to acquire. You can't deny its engaging romantic defiance, though. |