32 ideas
| 22338 | An unexamined life can be virtuous [Murdoch] |
| Full Idea: An unexamined life can be virtuous. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: Nice. A firm rejection of the intellectualist view of virtue, to which most Greeks subscribed. Jesus would have liked this one. |
| 22337 | Philosophy must keep returning to the beginning [Murdoch] |
| Full Idea: Philosophy has in a sense to keep trying to return to the beginning. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: This is a sign that philosophy is not like other subjects, and indicates that although the puzzles are not solved, they won't go away. Also that, unlike most other subjects, the pre-suppositions are not part of the subject. |
| 23563 | Philosophy moves continually between elaborate theories and the obvious facts [Murdoch] |
| Full Idea: There is a two-way movement in philosophy, a movement towards the building of elaborate theories, and a move back again towards the consideration of simple and obvious facts. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: Nice. Without the theories there is no philosophy, but without continual reference back to the obvious facts the theories are worthless. |
| 13838 | A decent modern definition should always imply a semantics [Hacking] |
| Full Idea: Today we expect that anything worth calling a definition should imply a semantics. | |
| From: Ian Hacking (What is Logic? [1979], §10) | |
| A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives. |
| 13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
| Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference. | |
| From: Ian Hacking (What is Logic? [1979], §06.2) | |
| A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic. |
| 13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
| Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction. | |
| From: Ian Hacking (What is Logic? [1979], §06.3) | |
| A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step). |
| 13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
| Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it. | |
| From: Ian Hacking (What is Logic? [1979], §08) |
| 13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
| Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication. | |
| From: Ian Hacking (What is Logic? [1979], §15) | |
| A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation? |
| 13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
| Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
| Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours. |
| 13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
| Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds. | |
| From: Ian Hacking (What is Logic? [1979], §13) |
| 13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
| Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties. | |
| From: Ian Hacking (What is Logic? [1979], §09) | |
| A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth. |
| 13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
| Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier. | |
| From: Ian Hacking (What is Logic? [1979], §11) | |
| A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea... |
| 13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
| Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic. | |
| From: Ian Hacking (What is Logic? [1979], §13) | |
| A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos. |
| 20475 | Maybe modal sentences cannot be true or false [Casullo] |
| Full Idea: Some people claim that modal sentences do not express truths or falsehoods. | |
| From: Albert Casullo (A Priori Knowledge [2002], 3.2) | |
| A reaction: I can only imagine this coming from a narrow hardline empiricist. It seems to me obvious that we make true or false statements about what is possible or impossible. |
| 20476 | If the necessary is a priori, so is the contingent, because the same evidence is involved [Casullo] |
| Full Idea: If one can only know a priori that a proposition is necessary, then one can know only a priori that a proposition is contingent. The evidence relevant to determining the latter is the same as that relevant to determining the former. | |
| From: Albert Casullo (A Priori Knowledge [2002], 3.2) | |
| A reaction: This seems a telling point, but I suppose it is obvious. If you see that the cat is on the mat, nothing in the situation tells you whether this is contingent or necessary. We assume it is contingent, but that may be an a priori assumption. |
| 20471 | Epistemic a priori conditions concern either the source, defeasibility or strength [Casullo] |
| Full Idea: There are three suggested epistemic conditions on a priori knowledge: the first regards the source of justification, the second regards the defeasibility of justification, and the third appeals to the strength of justification. | |
| From: Albert Casullo (A Priori Knowledge [2002], 2) | |
| A reaction: [compressed] He says these are all inspired by Kant. The non-epistemic suggested condition involve necessity or analyticity. The source would have to be entirely mental; the defeasibly could not be experiential; the strength would be certainty. |
| 20477 | The main claim of defenders of the a priori is that some justifications are non-experiential [Casullo] |
| Full Idea: The leading claim of proponents of the a priori is that sources of justification are of two significantly different types: experiential and nonexperiential. Initially this difference is marked at the phenomenological level. | |
| From: Albert Casullo (A Priori Knowledge [2002], 5) | |
| A reaction: He cites Plantinga and Bealer for the phenomenological starting point (that some knowledge just seems rationally obvious, certain, and perhaps necessary). |
| 20472 | Analysis of the a priori by necessity or analyticity addresses the proposition, not the justification [Casullo] |
| Full Idea: There is reason to view non-epistemic analyses of a priori knowledge (in terms of necessity or analyticity) with suspicion. The a priori concerns justification. Analysis by necessity or analyticity concerns the proposition rather than the justification. | |
| From: Albert Casullo (A Priori Knowledge [2002], 2.1) | |
| A reaction: [compressed] The fact that the a priori is entirely a mode of justification, rather than a type of truth, is the modern view, influenced by Kripke. Given that assumption, this is a good objection. |
| 20474 | 'Overriding' defeaters rule it out, and 'undermining' defeaters weaken in [Casullo] |
| Full Idea: A justified belief that a proposition is not true is an 'overriding' defeater, ...and the belief that a justification is inadequate or defective is an 'undermining' defeater. | |
| From: Albert Casullo (A Priori Knowledge [2002], n 40) | |
| A reaction: Sounds more like a sliding scale than a binary option. Quite useful, though. |
| 22341 | Literature is the most important aspect of culture, because it teaches understanding of living [Murdoch] |
| Full Idea: The most essential and fundamental aspect of culture is the study of literature, since this is an education in how to picture and understand human situations. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], i) | |
| A reaction: It is significant that literature belongs more clearly to a nation or community than does most music or painting. You learn about Russians from their literature, but not much from their music. |
| 22347 | Appreciating beauty in art or nature opens up the good life, by restricting selfishness [Murdoch] |
| Full Idea: The appreciation of beauty in art or nature is not only the easiest available spiritual exercise; it is also a completely adequate entry into (and not just analogy of) the good life, since it checks selfishness in the interest of seeing the real. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], II) | |
| A reaction: Not keen on 'spiritual' exercises, but I very much like 'seeing the real' as a promotion of the good life. The hard bit is to know what reality you are seeing in a work of art. [p.84] Her example is the sudden sight of a hovering kestrel. |
| 22339 | Love is a central concept in morals [Murdoch] |
| Full Idea: Love is a central concept in morals. ....[p.30] The central concept of morality is 'the individual' thought of as knowable by love, thought of in the light of the command 'Be ye therefore perfect'. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: This seems to be a critique of the chillier aspects of utilitarianism and Kantian duty. Love doesn't seem essential to Aristotle's concept of virtue either, and Murdoch's tradition seems to be Christian. I'm undecided about this idea. |
| 22348 | Ordinary human love is good evidence of transcendent goodness [Murdoch] |
| Full Idea: Is not ordinary human love ...striking evidence of a transcendental principle of good? | |
| From: Iris Murdoch (The Sovereignty of Good [1970], II) | |
| A reaction: Sorry to be mean, but I would say not. Love is tied up with sexual desire, and with family and tribal loyalty, and can be observed in quite humble animals. (Love, I should quickly add, is a very good thing indeed. Really). |
| 22343 | If I attend properly I will have no choices [Murdoch] |
| Full Idea: If I attend properly I will have no choices, and this is the ultimate condition to be aimed at. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: I take it this is an expression of what we now call Particularism. It is not just that every moral situation is subtly morally different, but that the particulars of the situation will lead directly to moral choices (in a 'healthy' agent). |
| 22349 | Art trains us in the love of virtue [Murdoch] |
| Full Idea: The enjoyment of art is a training in the love of virtue. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], III) | |
| A reaction: Very Aristotelian to talk of 'training'. Unfortunately it is children who have the greatest need for training, but most art is aimed at mature adults. Can you be too old to be trained by art, even if you enjoy it? |
| 22340 | It is hard to learn goodness from others, because their virtues are part of their personal history [Murdoch] |
| Full Idea: It is the historical, individual, nature of the virtues as actually exemplified which makes it difficult to learn goodness from another person. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: A penetrating remark, which strikes me as true. When confronted with a virtuous person you might want to acquire their virtue, just as you might want them to teach you algebra, but their virtues are too bound up with their individuality. |
| 22350 | Only trivial virtues can be possessed on their own [Murdoch] |
| Full Idea: It would be impossible to have only one virtue, unless it were a very trivial one such as thrift. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], III) | |
| A reaction: A nicely nuanced commitment to the unity of virtue. You might exhibit courage alone in a brute animal way, but the sort of courage we all admire is part of more extended virtues. |
| 22346 | Moral reflection and experience gradually reveals unity in the moral world [Murdoch] |
| Full Idea: Reflection rightly tends to unify the moral world, and increasing moral sophistication reveals increasing unity. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], II) | |
| A reaction: As an example she suggests asking what is the best type of courage. Connections to other virtues will emerge. That is a persuasive example. We all have strong views on what type of courage is the most admirable. |
| 22342 | Kantian existentialists care greatly for reasons for action, whereas Surrealists care nothing [Murdoch] |
| Full Idea: What may be called the Kantian wing and the Surrealist wing of existentialism may be distinguished by the degree of their interest in reasons for action, which diminishes to nothing at the Surrealist end. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], I) | |
| A reaction: Presumably for all existentialists moral decisions are the most important aspect of life, since they define what you are, but the Surrealist wing seem to be nihilists about that, so they barely count as existentialists. For them life is sleepwalking. |
| 22351 | Only a philosopher might think choices create values [Murdoch] |
| Full Idea: The ordinary person does not, unless corrupted by philosophy, believe that he creates values by his choices. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], III) | |
| A reaction: This looks like a swipe at Nietzsche, more than anyone. Sartre and co talk less about values, other than authenticity. Philosophy can definitely be corrupting. |
| 22345 | Moral philosophy needs a central concept with all the traditional attributes of God [Murdoch] |
| Full Idea: God was (or is) a single perfect transcendent non-representable and necessarily real object of attention. ....Moral philosophy should attempt to retain a central concept which has all these characteristics. | |
| From: Iris Murdoch (The Sovereignty of Good [1970], II) | |
| A reaction: This is a combination of middle Platonism (which sees the Form of the Good as the mind of God) and G.E. Moore's indefinable ideal of goodness. Murdoch connects this suggestion with the centrality of love in moral philosophy. I disagree. |