30 ideas
| 22496 | Wisdom only implies the knowledge achievable in any normal lifetime [Foot] |
| Full Idea: Wisdom implies no more knowledge and understanding than anyone of normal capacity can and should acquire in the course of an ordinary life. | |
| From: Philippa Foot (Natural Goodness [2001], 5) | |
| A reaction: Have philosophers stopped talking about wisdom precisely because you now need three university degrees to be considered even remotely good at phillosophy? Hence wisdom is an inferior attainment, because Foot is right. |
| 7786 | Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle] |
| Full Idea: Propositional logic can deal with negation, disjunction and conjunction of propositions, but predicate logic goes beyond it to deal with quantifiers, predicates and relations. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.1) | |
| A reaction: This is on the first page of an introduction to the next stage, which is to include modal notions like 'must' and 'possibly'. |
| 7798 | There are three axiom schemas for propositional logic [Girle] |
| Full Idea: The axioms of propositional logic are: A→(B→A); A→(B→C)→(A→B)→(A→C) ; and (¬A→¬B)→(B→A). | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |
| Full Idea: The operators of propositional logic are defined as follows: 'or' (v) is not-A implies B; 'and' (ampersand) is not A-implies-not-B; and 'identity' (three line equals) is A-implies-B and B-implies-A. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7797 | Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle] |
| Full Idea: An axiom system for a logic contains three elements: a set of axioms; a set of inference rules; and definitions for proofs and theorems. There are also definitions for the derivation of conclusions from sets of premises. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7794 | There are seven modalities in S4, each with its negation [Girle] |
| Full Idea: In S4 there are fourteen modalities: no-operator; necessarily; possibly; necessarily-possibly; possibly-necessarily; necessarily-possibly-necessarily; and possibly-necessarily-possibly (each with its negation). | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.5) | |
| A reaction: This is said to be 'more complex' than S5, but also 'weaker'. |
| 7793 | ◊p → □◊p is the hallmark of S5 [Girle] |
| Full Idea: The critical formula that distinguishes S5 from all others is: ◊p → □◊p. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.3) | |
| A reaction: If it is possible that it is raining, then it is necessary that it is possible that it is raining. But if it is possible in this world, how can that possibility be necessary in all possible worlds? |
| 7795 | S5 has just six modalities, and all strings can be reduced to those [Girle] |
| Full Idea: In S5 there are six modalities: no-operator; necessarily; and possibly (and their negations). In any sequence of operators we may delete all but the last to gain an equivalent formula. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.5) | |
| A reaction: Such drastic simplification seems attractive. Is there really no difference, though, between 'necessarily-possibly', 'possibly-possibly' and just 'possibly'? Could p be contingently possible in this world, and necessarily possible in another? |
| 7787 | Possible worlds logics use true-in-a-world rather than true [Girle] |
| Full Idea: In possible worlds logics a statement is true-in-a-world rather than just true. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.1) | |
| A reaction: This sounds relativist, but I don't think it is. It is the facts which change, not the concept of truth. So 'donkeys can talk' may be true in a world, but not in the actual one. |
| 7788 | Modal logic has four basic modal negation equivalences [Girle] |
| Full Idea: The four important logical equivalences in modal logic (the Modal Negation equivalences) are: ¬◊p↔□¬p, ◊¬p↔¬□p, □p↔¬◊¬p, and ◊p↔¬□¬p. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.2) | |
| A reaction: [Possibly is written as a diamond, necessarily a square] These are parallel to a set of equivalences between quantifiers in predicate logic. They are called the four 'modal negation (MN) equivalences'. |
| 7796 | Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle] |
| Full Idea: Modal logics were, for a long time, studied in terms of axiom systems. The advent of possible worlds semantics made it possible to study them in a semantic way as well. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
| Full Idea: Necessary implication is often called 'strict implication'. The sort of strict implication found in valid arguments, where the conjunction of the premises necessarily implies the conclusion, is often called 'entailment'. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.2) | |
| A reaction: These are basic concept for all logic. |
| 7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
| Full Idea: The truth trees method for establishing the validity of arguments and formulas is easy to use, and has the advantage that if an argument or formula is not valid, then a counter-example can be retrieved from the tree. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.4) |
| 7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
| Full Idea: It has been customary to see analytic truths as dividing into the logically necessary and the conceptually necessary. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 7.3) | |
| A reaction: I suspect that this neglected distinction is important in discussions of Quine's elimination of the analytic/synthetic distinction. Was Quine too influenced by what is logically necessary, which might shift with a change of axioms? |
| 7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
| Full Idea: Qualified modalities seem to form a hierarchy, if we say that 'the possibility that there might be no hunger' is possible logically, theoretically, physically, economically, and humanly. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 7.3) | |
| A reaction: Girle also mentions conceptual possibility. I take 'physically' to be the same as 'naturally'. I would take 'metaphysically' possible to equate to 'theoretically' rather than 'logically'. Almost anything might be logically possible, with bizarre logic. |
| 7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
| Full Idea: When one world generates another then it has 'access' to the world it generated. The accessibility relation between worlds is very important in possible worlds semantics. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.2) | |
| A reaction: This invites the obvious question what is meant by 'generates'. |
| 23694 | All criterions of practical rationality derive from goodness of will [Foot] |
| Full Idea: I want to say, baldly, that there is no criterion for practical rationality that is not derived from that of goodness of will. | |
| From: Philippa Foot (Natural Goodness [2001], 1) | |
| A reaction: Where does that put the successful and clever criminal? Presumably they are broadly irrational, but narrowly rational - but that is not very clear distinction. She says Kant's concept of the good will is too pure, and unrelated to human good. |
| 23686 | Moral reason is not just neutral, because morality is part of the standard of rationality [Foot, by Hacker-Wright] |
| Full Idea: In her late period she again reverses her thoughts on moral rationalism; …rather than a neutral rationality which fulfils desires, she argues that morality ought to be thought of as part of the standard of rationality itself. | |
| From: report of Philippa Foot (Natural Goodness [2001]) by John Hacker-Wright - Philippa Foot's Moral Thought Intro | |
| A reaction: This comes much closer to the Greek and Aristotelian concept of logos. They saw morality as inseparable from our judgements about how the world is. All 'sensible' thinking will involve what is good for humanity. |
| 23693 | Practical rationality must weigh both what is morally and what is non-morally required [Foot] |
| Full Idea: Different considerations are on a par, in that judgement about what is required by practical rationality must take account of their interaction: of the weight of the ones we call non-moral as well as those we call moral. | |
| From: Philippa Foot (Natural Goodness [2001], 1) | |
| A reaction: Her final settled view of rationalism in morality, it seems. The point is that moral considerations are not paramount, because she sees possible justifications for ignoring moral rules (like 'don't lie') in certain practical situations. |
| 23687 | Moral virtues arise from human nature, as part of what makes us good human beings [Foot, by Hacker-Wright] |
| Full Idea: In her later work she offers a view of the relationship of morality to human nature, arguing that the moral virtues are part of what makes us good as human beings. | |
| From: report of Philippa Foot (Natural Goodness [2001]) by John Hacker-Wright - Philippa Foot's Moral Thought Intro | |
| A reaction: In this phase she talks explicitly of the Aristotelian idea that successful function is the grounding of what is good for any living being, including humans. |
| 22493 | Sterility is a human defect, but the choice to be childless is not [Foot] |
| Full Idea: Lack of capacity to reproduce is a defect in a human being. But choice of childlessness and even celibacy is not thereby shown to be defective choice, because human good is not the same as plant or animal good. | |
| From: Philippa Foot (Natural Goodness [2001], 3) | |
| A reaction: Is failure to reproduce a defect in an animal? If goodness and virtue derive from function, it is hard to see how deliberate childlessness could be a human good, even if it is not a defect. Choosing to terminate a hereditary defect seems good. |
| 22492 | Virtues are as necessary to humans as stings are to bees [Foot] |
| Full Idea: Virtues play a necessary part in the life of human beings as do stings in the life of a bee. | |
| From: Philippa Foot (Natural Goodness [2001], 2) | |
| A reaction: This presumably rests on the Aristotelian idea that humans are essentially social (as opposed to solitary humans who choose to be social, perhaps in a contractual way, as Plato implies). |
| 22491 | Moral evaluations are not separate from facts, but concern particular facts about functioning [Foot] |
| Full Idea: A moral evaluation does not stand over against the statement of a matter of fact, but rather has to do with facts about a particular subject matter, as do evaluations of such things as sight and hearing in animals. | |
| From: Philippa Foot (Natural Goodness [2001], 1) | |
| A reaction: She avoids the word 'function', and only deals with living creatures, but she uses a 'good knife' as an example, and this Aristotelian view clearly applies to any machine which has a function. |
| 22497 | Deep happiness usually comes from the basic things in life [Foot] |
| Full Idea: Possible objects of deep happiness seem to be things that are basic in human life, such as home, and family, and work, and friendship. | |
| From: Philippa Foot (Natural Goodness [2001], 6) | |
| A reaction: I've not encountered discussion of 'deep' happiness before. I heard of an old man in tears because he had just seen a Purple Emperor butterfly for the first time. She makes it sound very conservative. How about mountaineering achievements? |
| 22498 | Happiness is enjoying the pursuit and attainment of right ends [Foot] |
| Full Idea: In my terminology 'happiness' is understood as the enjoyment of good things, meaning the enjoyment in attaining, and in pursuing, right ends. | |
| From: Philippa Foot (Natural Goodness [2001], 6) | |
| A reaction: A modified version of Aristotle's view, which she contrasts with McDowell's identification of happiness with the life of virtue. They all seem to have an optimistic hope that the pleasure in being a bit wicked is false happiness. |
| 23695 | Good actions can never be justified by the good they brings to their agent [Foot] |
| Full Idea: There is no good case for assessing the goodness of human action by reference only to good that each person brings to himself. | |
| From: Philippa Foot (Natural Goodness [2001], 1) | |
| A reaction: She observes that even non-human animals often act for non-selfish reasons. The significance of this is its rejection of her much earlier view that virtues are justified by the good they bring their possessor. |
| 22499 | We all know that just pretending to be someone's friend is not the good life [Foot] |
| Full Idea: We know perfectly well that it is not true that the best life would consist in successfully pretending friendship: having friends to serve one but without being a real friend oneself. | |
| From: Philippa Foot (Natural Goodness [2001], 7) | |
| A reaction: For some skallywags the achieving of something for nothing seems to be very much the good life, but not many of them want to exploit people who are seen to be their friends. |
| 22495 | Someone is a good person because of their rational will, not their body or memory [Foot] |
| Full Idea: To speak of a good person is to speak of an individual not in respect of his body, or of faculties such as sight and memory, but as concerns his rational will (his 'will as controllable by reason'). | |
| From: Philippa Foot (Natural Goodness [2001], 5) | |
| A reaction: She more or less agrees with Kant that the only truly good moral thing is a good will, though she has plenty of other criticisms of his views. |
| 22502 | Refraining from murder is not made good by authenticity or self-fulfilment [Foot] |
| Full Idea: If a stranger should come on us when we are sleeping he will not think it all right to kill us. …In human life as it is, this kind of action is not made good by authenticity or self-fulfilment in the one who does it. | |
| From: Philippa Foot (Natural Goodness [2001], 7) | |
| A reaction: A rare swipe from Foot at existentialism, which she hardly ever mentions. I find it hard to see these existential virtues as in any way moral. It means nothing to other citizens whether one of their number is 'authentic'. |
| 20543 | 'Social justice' is a confused idea, and inequalities need no justification [Hayek, by Swift] |
| Full Idea: Hayek thinks the whole idea of social justice involves a philosophical mistake, so that inequality doesn't really need justification in the first place. | |
| From: report of F.A. Hayek (The Mirage of Social Justice [1976]) by Adam Swift - Political Philosophy (3rd ed) 1 'Conc' | |
| A reaction: It is certainly hard to justify the claim that the state of nature involves equality, making its disturbance in need of justification. But surely inequalities in government policy (such as differential income tax) need justification? |