12 ideas
9540 | A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell] |
Full Idea: A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0. | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: In the interpreted version of the logic, 1 and 0 would become T (true) and F (false). The procedure seems to be called nowadays a 'valuation'. |
9541 | The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell] |
Full Idea: The Law of Transposition says that (P→Q) → (¬Q→¬P). | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: That is, if the consequent (Q) of a conditional is false, then the antecedent (P) must have been false. |
9543 | The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell] |
Full Idea: An axiomatic system is most naturally consistent iff no thesis is the negation of another thesis. It can be shown that every axiom is valid, that the transformation rules are validity-preserving, and if a wff α is valid, then ¬α is not valid. | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: [The labels 'soundness' and 'consistency' seem interchangeable here, with the former nowadays preferred] |
9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
Full Idea: To say that an axiom system is 'weakly complete' is to say that every valid wff of the system is derivable as a thesis. ..The system is 'strongly complete' if it cannot have any more theses than it has without falling into inconsistency. | |
From: GE Hughes/M Cresswell (An Introduction to Modal Logic [1968], Ch.1) | |
A reaction: [They go on to say that Propositional Logic is strongly complete, but Modal Logic is not] |
8978 | Events are made of other things, and are not fundamental to ontology [Bennett] |
Full Idea: Events are not basic items in the universe; they should not be included in any fundamental ontology...all the truths about them are entailed by and explained and made true by truths that do not involve the event concept. | |
From: Jonathan Bennett (Events and Their Names [1988], p.12), quoted by Peter Simons - Events 3.1 | |
A reaction: Given the variable time spans of events, their ability to coincide, their ability to contain no motion, their blatantly conventional component, and their recalcitrance to individuation, I say Bennett is right. |
22465 | We see a moral distinction between doing and allowing to happen [Foot] |
Full Idea: We have an intuition that there is a morally relevant distinction between what we do and what we allow to happen. | |
From: Philippa Foot (Morality, Action, and Outcome [1985], p.88) | |
A reaction: She says many deny this distinction, but she defends it. Presumably consequentialists deny the distinction. What is bad if I do it, but OK if I allow it to happen? Neglecting a victim to save others, she suggests. |
22466 | We see a moral distinction between our aims and their foreseen consequences [Foot] |
Full Idea: We have an intuition that there is a moral distinction between what we aim at and what we foresee as a result of what we do. | |
From: Philippa Foot (Morality, Action, and Outcome [1985], p.88) | |
A reaction: Cf. Idea 22465. This seems to be the classic doctrine of double effect. It is hard to defend the claim that we are only responsible for what we aim at. A wide assessment of consequences is a moral duty. Well-meaning fools are bad. |
22467 | Acts and omissions only matter if they concern doing something versus allowing it [Foot] |
Full Idea: The difference between acts and omissions is irrelevant to any moral issue except in so far as it corresponds to the distinction between allowing something to happen and being the agent to whom the happening can be ascribed. | |
From: Philippa Foot (Morality, Action, and Outcome [1985], p.89) | |
A reaction: The list of anyone's omissions is presumably infinite, but what they 'allow' must be in some way within their power. But what of something I can't now prevent, only because I failed to do some relevant task yesterday? |
22470 | A good moral system benefits its participants, and so demands reciprocity [Foot] |
Full Idea: It has been suggested that one criterion for a good moral system is that it should be possible to demand reciprocity from every individual because of the good the system renders to him. | |
From: Philippa Foot (Morality, Action, and Outcome [1985], p.104) | |
A reaction: Money seems to have this feature, that we mostly conform to the rules for its use, because we value the whole system. Foot accepts this, but says there are also other criteria, such as leaving freedom to live well (ie. not too puritanical). |
22468 | Virtues can have aims, but good states of affairs are not among them [Foot] |
Full Idea: Some virtues do give us aims, but nothing from within morality suggests the kind of good state of affairs which it would seem always to be our duty to promote. And why indeed should there be any such thing? | |
From: Philippa Foot (Morality, Action, and Outcome [1985], p.101) | |
A reaction: Isn't successful human functioning, such as heath, always to be desired? If honour is a worthy aim, doesn't that make being rightly honoured a desirable state of affairs? She is attacking consequentialism, but I'm not convinced here. |
22469 | Some virtues imply rules, and others concern attachment [Foot] |
Full Idea: Virtues such as justice consist mainly in adherence to rules of conduct, while those such as benevolence we might call virtues of attachment. | |
From: Philippa Foot (Morality, Action, and Outcome [1985], p.101) | |
A reaction: Not sure about 'attachment'. We should be benevolent towards people to whom we are not particularly attached. Courage doesn't fall into either group. |
10364 | Facts are about the world, not in it, so they can't cause anything [Bennett] |
Full Idea: Facts are not the sort of item that can cause anything. A fact is a true proposition (they say); it is not something in the world but is rather something about the world. | |
From: Jonathan Bennett (Events and Their Names [1988], p.22), quoted by Jonathan Schaffer - The Metaphysics of Causation 1.1 | |
A reaction: Compare 10361. Good argument, but maybe 'fact' is ambiguous. See Idea 10365. Events are said to be more concrete, and so can do the job, but their individuation also seems to depend on a description (as Davidson has pointed out). |