13 ideas
| 23367 | Even pointing a finger should only be done for a reason [Epictetus] |
| Full Idea: Philosophy says it is not right even to stretch out a finger without some reason. | |
| From: Epictetus (fragments/reports [c.57], 15) | |
| A reaction: The key point here is that philosophy concerns action, an idea on which Epictetus is very keen. He rather despise theory. This idea perfectly sums up the concept of the wholly rational life (which no rational person would actually want to live!). |
| 14970 | Normal system K has five axioms and rules [Cresswell] |
| Full Idea: Normal propositional modal logics derive from the minimal system K: wffs of PC are axioms; □(p⊃q)⊃(□p⊃□q); uniform substitution; modus ponens; necessitation (α→□α). | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1) |
| 14971 | D is valid on every serial frame, but not where there are dead ends [Cresswell] |
| Full Idea: If a frame contains any dead end or blind world, then D is not valid on that frame, ...but D is valid on every serial frame. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.1) |
| 14972 | S4 has 14 modalities, and always reduces to a maximum of three modal operators [Cresswell] |
| Full Idea: In S4 there are exactly 14 distinct modalities, and any modality may be reduced to one containing no more than three modal operators in sequence. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.2) | |
| A reaction: The significance of this may be unclear, but it illustrates one of the rewards of using formal systems to think about modal problems. There is at least an appearance of precision, even if it is only conditional precision. |
| 14973 | In S5 all the long complex modalities reduce to just three, and their negations [Cresswell] |
| Full Idea: S5 contains the four main reduction laws, so the first of any pair of operators may be deleted. Hence all but the last modal operator may be deleted. This leaves six modalities: p, ◊p, □p, and their negations. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.2) |
| 14976 | Reject the Barcan if quantifiers are confined to worlds, and different things exist in other worlds [Cresswell] |
| Full Idea: If one wants the quantifiers in each world to range only over the things that exist in that world, and one doesn't believe that the same things exist in every world, one would probably not want the Barcan formula. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.2.2) | |
| A reaction: I haven't quite got this, but it sounds to me like I should reject the Barcan formula (but Idea 9449!). I like a metaphysics to rest on the actual world (with modal properties). I assume different things could have existed, but don't. |
| 14974 | A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell] |
| Full Idea: A relation is 'Euclidean' if aRb and aRc imply bRc. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.2) | |
| A reaction: If a thing has a relation to two separate things, then those two things will also have that relation between them. If I am in the same family as Jim and as Jill, then Jim and Jill are in the same family. |
| 14975 | A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell] |
| Full Idea: A de dicto necessary truth says that something is φ, that this proposition is a necessary truth, i.e. that in every accessible world something (but not necessarily the same thing in each world) is φ. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.2.1) | |
| A reaction: At last, a really clear and illuminating account of this term! The question is then invited of what is the truthmaker for a de dicto truth, assuming that the objects themselves are truthmakers for de re truths. |
| 4125 | Hare says I acquire an agglomeration of preferences by role-reversal, leading to utilitarianism [Hare, by Williams,B] |
| Full Idea: In Hare's theory I apply a "role-reversal test", and then acquire an actual agglomeration of preferences that apply to the hypothetical situation. The result is utilitarianism. | |
| From: report of Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981]) by Bernard Williams - Ethics and the Limits of Philosophy Ch.5 | |
| A reaction: It hits that traditional stumbling block, of why I should care about the preferences of others. Pure reason and empathy are the options (Kant or Hume). I may, however, lack both. |
| 4126 | If we have to want the preferences of the many, we have to abandon our own deeply-held views [Williams,B on Hare] |
| Full Idea: Hare's version of utilitarianism requires an agent to abandon any deeply held principle or conviction if a large enough aggregate of contrary preferences, of whatever kind, favours a contrary action. | |
| From: comment on Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981]) by Bernard Williams - Ethics and the Limits of Philosophy Ch.5 | |
| A reaction: This nicely attacks any impersonal moral theory, whether it is based on reason or preferences. But where did my personal ideals come from? |
| 4127 | If morality is to be built on identification with the preferences of others, I must agree with their errors [Williams,B on Hare] |
| Full Idea: If there is to be total identification with others, then if another's preferences are mistaken, the preferences I imagine myself into are equally mistaken, and if 'identification' is the point, they should remain mistaken. | |
| From: comment on Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981]) by Bernard Williams - Ethics and the Limits of Philosophy Ch.5 | |
| A reaction: Yes. The core of morality must be judgement. Robots can implement universal utilitarian rules, but they could end up promoting persecutions of minorities. |
| 22483 | A judgement is presciptive if we expect it to be acted on [Hare] |
| Full Idea: We say something prescriptive if and only if, for some act A, some situation S and some person R, if P were to assent (orally) to what we say, and not, in S, do A, he logically must be assenting insincerely. | |
| From: Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981], p.21), quoted by Philippa Foot - Does Moral Subjectivism Rest on a Mistake? p.190 | |
| A reaction: Foot offers this as Hare's most explicit definition. The use of algebra strikes me as ludicrous. In logic letters have the virtue of not shifting their meaning during an argument, but that is not required here. |
| 4360 | By far the easiest way of seeming upright is to be upright [Hare] |
| Full Idea: By far the easiest way of seeming upright is to be upright. | |
| From: Richard M. Hare (Moral Thinking: Its Levels,Method and Point [1981], Ch.11) | |
| A reaction: Yes. This is the route which takes us from enlightened self-interest to a vision of true morality. Virtue is found to be its own reward, thought that is not how we became virtuous to begin with. |