21 ideas
| 8378 | Philosophers usually learn science from each other, not from science [Russell] |
| Full Idea: Philosophers are too apt to take their views on science from each other, not from science. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.178) | |
| A reaction: This wasn't true of Russell, but it is certainly true of me. I rely on philosophical researchers to find the interesting bits of science for me (like blindsight). Memo to myself: read more science. |
| 17884 | Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner] |
| Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro) |
| 17893 | 'Reflection principles' say the whole truth about sets can't be captured [Koellner] |
| Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1) |
| 17894 | We have no argument to show a statement is absolutely undecidable [Koellner] |
| Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3) |
| 17890 | There are at least eleven types of large cardinal, of increasing logical strength [Koellner] |
| Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable). | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) | |
| A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway] |
| 17887 | PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner] |
| Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem]. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1) | |
| A reaction: Each expansion brings a limitation, but then you can expand again. |
| 17891 | Arithmetical undecidability is always settled at the next stage up [Koellner] |
| Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) |
| 8375 | 'Necessary' is a predicate of a propositional function, saying it is true for all values of its argument [Russell] |
| Full Idea: 'Necessary' is a predicate of a propositional function, meaning that it is true for all possible values of its argument or arguments. Thus 'If x is a man, x is mortal' is necessary, because it is true for any possible value of x. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.175) | |
| A reaction: This is presumably the intermediate definition of necessity, prior to modern talk of possible worlds. Since it is a predicate about functions, it is presumably a metalinguistic concept, like the semantic concept of truth. |
| 3546 | 'Phronesis' should translate as 'practical intelligence', not as prudence [Annas] |
| Full Idea: The best translation of 'phronesis' is probably not 'prudence' (which implies a non-moral motive), or 'practical wisdom' (which makes it sound contemplative), but 'practical intelligence', or just 'intelligence'. | |
| From: Julia Annas (The Morality of Happiness [1993], 2.3) |
| 3547 | Epicureans achieve pleasure through character development [Annas] |
| Full Idea: Since having a virtue does not reduce to performing certain kinds of acts, the Epicurean will achieve pleasure only by aiming at being a certain kind of person. | |
| From: Julia Annas (The Morality of Happiness [1993], 2.4) | |
| A reaction: No Epicurean would want to merely possess virtues, without enacting them. I assume that virtues are sought as guides to finding the finest pleasures (such as friendship). |
| 3543 | Cyrenaics pursue pleasure, but don't equate it with happiness [Annas] |
| Full Idea: Cyrenaics claimed our final good was pleasure, best achieved by seeking maximum intensity of pleasurable experiences, but they explicitly admitted that this was not happiness. | |
| From: Julia Annas (The Morality of Happiness [1993], 1) |
| 3541 | Ancient ethics uses attractive notions, not imperatives [Annas] |
| Full Idea: Instead of modern 'imperative' notions of ethics (involving obligation, duty and rule-following), ancient ethics uses 'attractive' notions like those of goodness and worth | |
| From: Julia Annas (The Morality of Happiness [1993], Intro) |
| 3550 | Principles cover life as a whole, where rules just cover actions [Annas] |
| Full Idea: Principles concern not just types of actions, but one's life as a whole, grasping truths about the nature of justice, and the like; they explain rules, giving the 'why' and not just the 'what'. | |
| From: Julia Annas (The Morality of Happiness [1993], 2.4) |
| 3551 | Virtue theory tries to explain our duties in terms of our character [Annas] |
| Full Idea: An ethics of virtue moves from an initial interest in what we ought to do to an interest in the kinds of people we are and hope to be, because the latter is taken to be the best way of understanding the former. | |
| From: Julia Annas (The Morality of Happiness [1993], 2.5) |
| 3552 | If excessively good actions are admirable but not required, then duty isn't basic [Annas] |
| Full Idea: Supererogatory actions are admirable and valuable, and we praise people for doing them, but they do not generate obligations to perform them, which casts doubt on obligation as the basic notion in ethics. | |
| From: Julia Annas (The Morality of Happiness [1993], 2.6) |
| 3542 | We should do good when necessary, not maximise it [Annas] |
| Full Idea: Why should I want to maximise my acting courageously? I act courageously when it is required. | |
| From: Julia Annas (The Morality of Happiness [1993], 1) |
| 4396 | The law of causality is a source of confusion, and should be dropped from philosophy [Russell] |
| Full Idea: The law of causality, I believe, like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.173) | |
| A reaction: A bold proposal which should be taken seriously. However, if we drop it from scientific explanation, we may well find ourselves permanently stuck with it in 'folk' explanation. What is the alternative? |
| 8376 | If causes are contiguous with events, only the last bit is relevant, or the event's timing is baffling [Russell] |
| Full Idea: A cause is an event lasting for a finite time, but if cause and effect are contiguous then the earlier part of a changing cause can be altered without altering the effect, and a static cause will exist placidly for some time and then explode into effect. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.177) | |
| A reaction: [very compressed] He concludes that they can't be contiguous (and eventually rejects cause entirely). This kind of problem is the sort of thing that only bothers philosophers - the question of how anything can happen at all. Why change? |
| 8380 | Striking a match causes its igniting, even if it sometimes doesn't work [Russell] |
| Full Idea: A may be the cause of B even if there actually are cases of B not following A. Striking a match will be the cause of its igniting, in spite of the fact that some matches are damp and fail to ignite. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.185) | |
| A reaction: An important point, although defenders of the constant conjunction view can cope with it. There is a further regularity between dampness of matches and their failure to strike. |
| 8379 | In causal laws, 'events' must recur, so they have to be universals, not particulars [Russell] |
| Full Idea: An 'event' (in a statement of the 'law of causation') is intended to be something that is likely to recur, since otherwise the law becomes trivial. It follows that an 'event' is not some particular, but a universal of which there may be many instances. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.179) | |
| A reaction: I am very struck by this. It may be a key insight into understanding what a law of nature actually is. It doesn't follow that we must be realists about universals, but the process of abstraction from particulars is at the heart of generalisation. |
| 8381 | The constancy of scientific laws rests on differential equations, not on cause and effect [Russell] |
| Full Idea: It is not in the sameness of causes and effects that the constancy of scientific law consists, but in sameness of relations. And even 'sameness of relations' is too simple a phrase; 'sameness of differential equations' is the only correct phrase. | |
| From: Bertrand Russell (On the Notion of Cause [1912], p.186) | |
| A reaction: This seems to be a commitment to the regularity view, since there is nothing more to natural law than that the variables keeping obeying the equations. It also seems to be a very instrumentalist view. |