20 ideas
| 12184 | Logical necessity overrules all other necessities [McFetridge] |
| Full Idea: If it is logically necessary that if p then q, then there is no other sense of 'necessary' in which it is not necessary that if p then q. | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §1) | |
| A reaction: The thesis which McFetridge proposes to defend. The obvious rival would be metaphysical necessity, and the rival claim would presumably be that things are only logically necessary if that is entailed by a metaphysical necessity. Metaphysics drives logic. |
| 15083 | The fundamental case of logical necessity is the valid conclusion of an inference [McFetridge, by Hale] |
| Full Idea: McFetridge's conception of logical necessity is one which sees the concept as receiving its fundamental exemplification in the connection between the premiss and conclusion of a deductively valid inference. | |
| From: report of Ian McFetridge (Logical Necessity: Some Issues [1986]) by Bob Hale - Absolute Necessities 2 | |
| A reaction: This would mean that p could be logically necessary but false (if it was a valid argument from false premisses). What if it was a valid inference in a dodgy logical system (including 'tonk', for example)? |
| 15084 | In the McFetridge view, logical necessity means a consequent must be true if the antecedent is [McFetridge, by Hale] |
| Full Idea: McFetridge's view proves that if the conditional corresponding to a valid inference is logically necessary, then there is no sense in which it is possible that its antecedent be true but its consequent false. ..This result generalises to any statement. | |
| From: report of Ian McFetridge (Logical Necessity: Some Issues [1986]) by Bob Hale - Absolute Necessities 2 | |
| A reaction: I am becoming puzzled by Hale's assertion that logical necessity is 'absolute', while resting his case on a conditional. Are we interested in the necessity of the inference, or the necessity of the consequent? |
| 12180 | Logical necessity requires that a valid argument be necessary [McFetridge] |
| Full Idea: There will be a legitimate notion of 'logical' necessity only if there is a notion of necessity which attaches to the claim, concerning a deductively valid argument, that if the premisses are true then so is the conclusion. | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §1) | |
| A reaction: He quotes Aristotle's Idea 11148 in support. Is this resting a stronger idea on a weaker one? Or is it the wrong way round? We endorse validity because we see the necessity; we don't endorse necessity because we see 'validity'. |
| 12181 | Traditionally, logical necessity is the strongest, and entails any other necessities [McFetridge] |
| Full Idea: The traditional crucial assumption is that logical necessity is the strongest notion of necessity. If it is logically necessary that p, then it is necessary that p in any other use of the notion of necessity there may be (physically, practically etc.). | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §1) | |
| A reaction: Sounds right. We might say it is physically necessary simply because it is logically necessary, and even that it is metaphysically necessary because it is logically necessary (required by logic). Logical possibility is hence the weakest kind? |
| 12183 | It is only logical necessity if there is absolutely no sense in which it could be false [McFetridge] |
| Full Idea: Is there any sense in which, despite an ascription of necessity to p, it is held that not-p is possible? If there is, then the original claim then it was necessary is not a claim of 'logical' necessity (which is the strongest necessity). | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §1) | |
| A reaction: See Idea 12181, which leads up to this proposed "test" for logical necessity. McFetridge has already put epistemic ('for all I know') possibility to one side. □p→¬◊¬p is the standard reading of necessity. His word 'sense' bears the burden. |
| 12192 | The mark of logical necessity is deduction from any suppositions whatever [McFetridge] |
| Full Idea: The manifestation of the belief that a mode of inference is logically necessarily truth-preserving is the preparedness to employ that mode of inference in reasoning from any set of suppositions whatsoever. | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §4) | |
| A reaction: He rests this on the idea of 'cotenability' of the two sides of a counterfactual (in Mill, Goodman and Lewis). There seems, at first blush, to be a problem of the relevance of the presuppositions. |
| 12182 | We assert epistemic possibility without commitment to logical possibility [McFetridge] |
| Full Idea: Time- and person-relative epistemic possibility can be asserted even when logical possibility cannot, such as undecided mathematical propositions. 'It may be that p' just comes to 'For all I know, not-p'. | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §1) | |
| A reaction: If it is possible 'for all I know', then it could be actual for all I know, and if we accept that it might be actual, we could hardly deny that it is logically possible. Logical and epistemic possibilities of mathematical p stand or fall together. |
| 12187 | Objectual modal realists believe in possible worlds; non-objectual ones rest it on the actual world [McFetridge] |
| Full Idea: The 'objectual modal realist' holds that what makes modal beliefs true are certain modal objects, typically 'possible worlds'. ..The 'non-objectual modal realist' says modal judgements are made true by how things stand with respect to this world. | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §2) | |
| A reaction: I am an enthusiastic 'non-objectual modal realist'. I accept the argument that real possible worlds have no relevance to the actual world, and explain nothing (see Jubien). The possibilities reside in the 'powers' of this world. See Molnar on powers. |
| 12186 | Modal realists hold that necessities and possibilities are part of the totality of facts [McFetridge] |
| Full Idea: The 'modal realist' holds that part of the totality of what is the case, the totality of facts, are such things as that certain events could have happened, certain propositions are necessarily true, if this happened then that would have been the case. | |
| From: Ian McFetridge (Logical Necessity: Some Issues [1986], §2) | |
| A reaction: I am an enthusiastic modal realist. If the aim of philosophy is 'to understand' (and I take that to be the master idea of the subject) then no understanding is possible which excludes the possibilities and necessities in things. |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| Full Idea: In singing and playing the lyre, a boy will be likely to reveal not only courage and moderation, but also justice. | |
| From: Damon (fragments/reports [c.460 BCE], B4), quoted by (who?) - where? |
| 21740 | I doubt whether ethics is part of philosophy [Russell] |
| Full Idea: I hardly think myself that ethics ought to be included in the domain of philosophy. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch.22) | |
| A reaction: He declines to give his reasons. The implication of the chapter is that ethics is essentially a social and political matter, so that individual ethical guidelines are unimportant. Maybe the woolliness of ethics was also an impediment. |
| 21741 | 'You ought to do p' primarily has emotional content, expressing approval [Russell] |
| Full Idea: A sentence like 'You ought to do so-and-so' primarily has an emotional content. It means ' this is the act towards which I feel the emotion of approval'. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: I don't understand how I can say 'you ought to do p', and very clearly mean that the situation would be altogether better if p, only to be told by some philosopher that what I thought was a sensible judgement is actually an emotional outburst. |
| 21746 | Unlike hate, all desires can be satisfied by love [Russell] |
| Full Idea: If harmonious desires are what we should seek, love is better than hate, since, when two people love each other, both can be satisfied, whereas when they hate each other one at most can achieve the object of his desire. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: A wonderful example of cool philosophical objectivity! Of course it is not true, because the fact that two people love one another doesn't not prevent them from having some incompatible desires, as every couple knows. |
| 21747 | Goodness is a combination of love and knowledge [Russell] |
| Full Idea: The good life is one inspired by love and guided by knowledge. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: Forty years later, Russell's famous filmed message to posteriority said exactly this. In decision making, get the facts; in relationships, show love and tolerance. I find both parts inspiring. |
| 21743 | In wartime, happiness is hating the enemy, because it gives the war a purpose [Russell] |
| Full Idea: During and immediately after the war [14-18], those who hated the Germans were happier than those who still regarded them as human beings, because they could feel that what was being done served a good purpose. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: A striking remark. There are lots of situations where hatred seems to increase happiness. Russell is roughly defending consequentialism. |
| 21742 | Originally virtue was obedience, to gods, government, or custom [Russell] |
| Full Idea: Historically, virtue consisted at first of obedience to authority, whether that of the gods, the government, or custom. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: Russell proceeds to demolish such a theory, which he finds it fairly easy to do. In Nietzsche's terms, he is only describing slave virtue. Each role in the world has its own virtues (and functions). Which gods are the most virtuous? |
| 21745 | Act so as to produce harmonious rather than discordant desires [Russell] |
| Full Idea: The supreme moral rule should be: Act so as to produce harmonious rather than discordant desires. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: Russell makes no reference to Kant, but this is obviously intended to rebut the more rationalist Kantian view of what is imperative. The use of 'harmonious' chimes in best with Plato's account of the soul in 'Republic'. |
| 21744 | Legally curbing people's desires is inferior to improving their desires [Russell] |
| Full Idea: To force a man to curb his desires, as we do by the criminal law, is not nearly so satisfactory as to cause him genuinely to feel the desires which promote socially harmonious conduct. | |
| From: Bertrand Russell (An Outline of Philosophy [1927], Ch 22) | |
| A reaction: It is hard to disagree, but improving the desires of selfish and even vicious people is a rather challenging task. |
| 22891 | We could be aware of time if senses briefly vibrated, extending their experience of movement [Russell, by Bardon] |
| Full Idea: Russell suggested, in defence of an empiricist theory of time-awareness, that a sense organ goes on vibrating, like a piano string, for while after the stimulation. Thus we can see the movement of a second hand, seen in several places at once. | |
| From: report of Bertrand Russell (An Outline of Philosophy [1927]) by Adrian Bardon - Brief History of the Philosophy of Time 2 'Realism' | |
| A reaction: Hm. If they were vibrating the last experience, they couldn't pick up the new one. When something fast happens the brain resonates fortissimo! If your eyes are moving it will be different neurons that get fired at each instant. |