13 ideas
| 14626 | In S5 matters of possibility and necessity are non-contingent [Williamson] |
| Full Idea: In system S5 matters of possibility and necessity are always non-contingent. | |
| From: Timothy Williamson (Modal Logic within Counterfactual Logic [2010], 3) | |
| A reaction: This will be because if something is possible in one world (because it can be seen to be true in some possible world) it will be possible for all worlds (since they can all see that world in S5). |
| 18529 | Relations are expressed either as absolute facts, or by a relational concept [William of Ockham] |
| Full Idea: Socrates and Plato are similar if they are both white. Yet the mind can express this either by an 'absolute concept' (as 'Socrates is white' and 'Plato is white'), or by a 'relative concept', as 'Socrates is similar to Plato with respect to whiteness. | |
| From: William of Ockham (Seven Quodlibets [1332], VI q.25), quoted by John Heil - The Universe as We Find It 7 | |
| A reaction: Presumably he takes the facts of the matter to be the absolute concept, and the relative concept to be a contribution of the intellect. |
| 16779 | Cut wood doesn't make a new substance, but seems to make separate subjects [William of Ockham] |
| Full Idea: When a piece of wood is divided in two halves, no new substance is generated. But there are now two substances, or the accidents of the two halves would be without a subject. They existed before hand, and were one piece of wood, but not in the same place. | |
| From: William of Ockham (Seven Quodlibets [1332], IV.19), quoted by Richard S. Westfall - Never at Rest: a biography of Isaac Newton 26.2 | |
| A reaction: A nice example, demonstrating that there are substances within substances, contrary to the view of Duns Scotus. If a substance is just a subject for properties, it is hard to know what to make of this case. |
| 16757 | Hot water naturally cools down, which is due to the substantial form of the water [William of Ockham] |
| Full Idea: It is clear to the senses that hot water, if left to its own nature, reverts to coldness; this coldness cannot be caused by anything other than the substantial form of the water. | |
| From: William of Ockham (Seven Quodlibets [1332], III.6), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 24.4 | |
| A reaction: Unfortunately this is very bad science (even for its time), but it shows how many scholastics treated hylomorphism as a very physical and causal theory. |
| 14625 | Necessity is counterfactually implied by its negation; possibility does not counterfactually imply its negation [Williamson] |
| Full Idea: Modal thinking is logically equivalent to a type of counterfactual thinking. ...The necessary is that which is counterfactually implied by its own negation; the possible is that which does not counterfactually imply its own negation. | |
| From: Timothy Williamson (Modal Logic within Counterfactual Logic [2010], 1) | |
| A reaction: I really like this, because it builds modality on ordinary imaginative thinking. He says you just need to grasp counterfactuals, and also negation and absurdity, and you can then understand necessity and possibility. We can all do that. |
| 14623 | Strict conditionals imply counterfactual conditionals: □(A⊃B)⊃(A□→B) [Williamson] |
| Full Idea: The strict conditional implies the counterfactual conditional: □(A⊃B) ⊃ (A□→B) - suppose that A would not have held without B holding too; then if A had held, B would also have held. | |
| From: Timothy Williamson (Modal Logic within Counterfactual Logic [2010], 1) | |
| A reaction: [He then adds a reading of his formula in terms of possible worlds] This sounds rather close to modus ponens. If A implies B, and A is actually the case, what have you got? B! |
| 14624 | Counterfactual conditionals transmit possibility: (A□→B)⊃(◊A⊃◊B) [Williamson] |
| Full Idea: The counterfactual conditional transmits possibility: (A□→B) ⊃ (◊A⊃◊B). Suppose that if A had held, B would also have held; the if it is possible for A to hold, it is also possible for B to hold. | |
| From: Timothy Williamson (Modal Logic within Counterfactual Logic [2010], 1) |
| 14531 | Rather than define counterfactuals using necessity, maybe necessity is a special case of counterfactuals [Williamson, by Hale/Hoffmann,A] |
| Full Idea: Instead of regarding counterfactuals as conditionals restricted to a range of possible worlds, we can define the necessity operator by means of counterfactuals. Metaphysical necessity is a special case of ordinary counterfactual thinking. | |
| From: report of Timothy Williamson (Modal Logic within Counterfactual Logic [2010]) by Bob Hale/ Aviv Hoffmann - Introduction to 'Modality' 2 | |
| A reaction: [compressed] I very much like Williamson's approach, of basing these things on the ordinary way that ordinary people think. To me it is a welcome inclusion of psychology into metaphysics, which has been out in the cold since Frege. |
| 14628 | Imagination is important, in evaluating possibility and necessity, via counterfactuals [Williamson] |
| Full Idea: Imagination can be made to look cognitively worthless. Once we recall its fallible but vital role in evaluating counterfactual conditionals, we should be more open to the idea that it plays such a role in evaluating claims of possibility and necessity. | |
| From: Timothy Williamson (Modal Logic within Counterfactual Logic [2010], 6) | |
| A reaction: I take this to be a really important idea, because it establishes the importance of imagination within the formal framework of modern analytic philosopher (rather than in the whimsy of poets and dreamers). |
| 9102 | If an animal approached from a distance, we might abstract 'animal' from one instance [William of Ockham] |
| Full Idea: It seems possible that the concept of a genus could be abstracted from one individual, let us say, the concept 'animal', as in the case of one approaching from a distance, when I see enough to judge that I am seeing an animal. | |
| From: William of Ockham (Seven Quodlibets [1332], I Q xiii) | |
| A reaction: This is a rather individualistic view of abstraction, ignoring the shared language and culture. It is hard to imagine a truly virgin mind coming up with the concept after one encounter. The concept 'mind-boggling' seems more likely. |
| 9114 | There are no secure foundations to prove the separate existence of mind, in reason or experience [William of Ockham] |
| Full Idea: The existence of an immaterial 'intellective soul' ..cannot be demonstrated; for every reason by which we try to prove it assumes something that is doubtful for a man who follows only his natural reason. Neither can it be proved by experience. | |
| From: William of Ockham (Seven Quodlibets [1332], I Q x) | |
| A reaction: This is splendid honesty from a medieval monk. How would such a clear thinker have responded to modern brain research? Colin McGinn still maintains William's view, despite modern knowledge. Our ignorance produced conceptual dualism. |
| 5845 | Niceratus learnt the whole of Homer by heart, as a guide to goodness [Xenophon] |
| Full Idea: Niceratus said that his father, because he was concerned to make him a good man, made him learn the whole works of Homer, and he could still repeat by heart the entire 'Iliad' and 'Odyssey'. | |
| From: Xenophon (Symposium [c.391 BCE], 3.5) | |
| A reaction: This clearly shows the status which Homer had in the teaching of morality in the time of Socrates, and it is precisely this acceptance of authority which he was challenging, in his attempts to analyse the true basis of virtue |
| 9115 | To love God means to love whatever God wills to be loved [William of Ockham] |
| Full Idea: To love God above all means to love whatever God wills to be loved. | |
| From: William of Ockham (Seven Quodlibets [1332], III Q xiii) | |
| A reaction: A striking thought, which could be meaningful to the non-religious. Is it possible to form an image of what a perfect and ideal mind would love most? This might generate a set of universal values. It is tricky to find out what an actual God loves. |