13 ideas
15086 | Absolute necessity might be achievable either logically or metaphysically [Hale] |
Full Idea: Maybe peaceful co-existence between absolute logical necessity and absolute metaphysical necessity can be secured, ..and absolute necessity is their union. ...However, a truth would then qualify as absolutely necessary in two quite different ways. | |
From: Bob Hale (Absolute Necessities [1996], 4) | |
A reaction: Hale is addressing a really big question for metaphysic (absolute necessity) which others avoid. In the end he votes for rejecting 'metaphysical' necessity. I am tempted to vote for rejecting logical necessity (as being relative). 'Absolute' is an ideal. |
8261 | Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute [Hale] |
Full Idea: It might be metaphysically necessary that p but logically possible that not-p, so that metaphysical necessity is not, after all, absolute. | |
From: Bob Hale (Absolute Necessities [1996]), quoted by E.J. Lowe - The Possibility of Metaphysics 1.5 | |
A reaction: Lowe presents this as dilemma, but it sounds fine to me. Flying pigs etc. have no apparent logical problems, but I can't conceive of a possible world where pigs like ours fly in a world like ours. Earthbound pigs may be metaphysically necessary. |
15081 | A strong necessity entails a weaker one, but not conversely; possibilities go the other way [Hale] |
Full Idea: One type of necessity may be said to be 'stronger' than another when the first always entails the second, but not conversely. This will obtain only if the possibility of the first is weaker than the possibility of the second. | |
From: Bob Hale (Absolute Necessities [1996], 1) | |
A reaction: Thus we would normally say that if something is logically necessary (a very strong claim) then it will have to be naturally necessary. If something is naturally possible, then clearly it will have to be logically possible. Sounds OK. |
15080 | 'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true) [Hale] |
Full Idea: Necessity is 'relative' if a claim of φ-necessary that p just claims that it is a logical consequence of some statements Φ that p. We have a 'strong' version if we add that the statements in Φ are all true, and a 'weak' version if not. | |
From: Bob Hale (Absolute Necessities [1996], 1) | |
A reaction: I'm not sure about 'logical' consequence here. It may be necessary that a thing be a certain way in order to qualify for some category (which would be 'relative'), but that seems like 'sortal' necessity rather than logical. |
15082 | Metaphysical necessity says there is no possibility of falsehood [Hale] |
Full Idea: Friends of metaphysical necessity would want to hold that when it is metaphysically necessary that p, there is no good sense of 'possible' (except, perhaps, an epistemic one) in which it is possible that not-p. | |
From: Bob Hale (Absolute Necessities [1996], 2) | |
A reaction: We might want to say which possible worlds this refers to (and presumably it won't just be in the actual world). The normal claim would refer to all possible worlds. Adding a '...provided that' clause moves it from absolute to relative necessity. |
15085 | 'Broadly' logical necessities are derived (in a structure) entirely from the concepts [Hale] |
Full Idea: 'Broadly' logical necessities are propositions whose truth derives entirely from the concepts involved in them (together, of course, with relevant structure). | |
From: Bob Hale (Absolute Necessities [1996], 3) | |
A reaction: Is the 'logical' part of this necessity bestowed by the concepts, or by the 'structure' (which I take to be a logical structure)? |
15088 | Logical necessities are true in virtue of the nature of all logical concepts [Hale] |
Full Idea: The logical necessities can be taken to be the propositions which are true in virtue of the nature of all logical concepts. | |
From: Bob Hale (Absolute Necessities [1996], p.10) | |
A reaction: This is part of his story of essences giving rise to necessities. His proposal sounds narrow, but logical concepts may have the highest degree of generality which it is possible to have. It must be how the concepts connect that causes the necessities. |
15087 | Conceptual necessities are made true by all concepts [Hale] |
Full Idea: Conceptual necessities can be taken to be propositions which are true in virtue of the nature of all concepts. | |
From: Bob Hale (Absolute Necessities [1996], p.9) | |
A reaction: Fine endorse essences for these concepts. Could we then come up with a new concept which contradicted all the others, and destroyed the necessity? Yes, presumably. Presumably witchcraft and astrology are full of 'conceptual necessities'. |
21386 | We should accept as explanations all the plausible ways in which something could come about [Epicurus] |
Full Idea: The phases of the Moon could happen in all the ways [at least four] which the phenomena in our experience suggest for the explanation of this kind of thing - as long as one is not so enamoured of unique explanations as to groundlessly reject the others. | |
From: Epicurus (Letter to Pythocles [c.292 BCE], 94) | |
A reaction: Very interesting, for IBE. While you want to embrace the 'best', it is irrational to reject all of the other candidates, simply because you want a single explanation, if there are no good grounds for the rejection. |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |
14051 | A cosmos is a collection of stars and an earth, with some sort of boundary, movement and shape [Epicurus] |
Full Idea: A cosmos is a circumscribed portion of the heavens containing stars and an earth; it is separated from the unlimited, with a boundary which is rare or dense; it is revolving or stationary; it is round or triangular, or some shape. All these are possible. | |
From: Epicurus (Letter to Pythocles [c.292 BCE], 88) | |
A reaction: Notice that there seem to exist the 'heavens' which extend beyond the cosmos. See Idea 14036, saying that there are many other cosmoi in the heavens. |
1828 | God does not intervene in heavenly movements, but is beyond all action and perfectly happy [Epicurus] |
Full Idea: Let us beware of making the Deity interpose in heavenly movements, for that being we ought to suppose exempt from all occupation and perfectly happy. | |
From: Epicurus (Letter to Pythocles [c.292 BCE]), quoted by Diogenes Laertius - Lives of Eminent Philosophers 10.25 |