10 ideas
| 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) |
| 22481 | There is no restitution after a dilemma, if it only involved the agent, or just needed an explanation [Foot, by PG] |
| Full Idea: The 'remainder' after a dilemma can't be a matter of apology and restitution, because the dilemma may only involve the agent's own life, and in the case of broken promises we only owe an explanation, if the breaking is justifiable. | |
| From: report of Philippa Foot (Moral Dilemmas Revisited [1995], p.183) by PG - Db (ideas) | |
| A reaction: But what if someone has been financially ruined by it? If the agent feels guilty about that, is getting over it the rational thing to do? (Foot says that is an new obligation, and not part of the original dilemma). |
| 22482 | I can't understand how someone can be necessarily wrong whatever he does [Foot] |
| Full Idea: I do not see how …we can know how to interpret the idea of a situation in which someone will necessarily be wrong whatever he does. | |
| From: Philippa Foot (Moral Dilemmas Revisited [1995], p.188) | |
| A reaction: Seems right. If you think of hideous dilemmas (frequent in wartime), there must always be a right thing to do (or two equally right things to do), even if the outcome is fairly hideous. Just distinguish the right from the good. |
| 23812 | Force is what turns man into a thing, and ultimately into a corpse [Weil] |
| Full Idea: To define 'force' - it is that x that turns anybody who is subjected to it into a thing. Exercised to the limit, it turns man into a thing in the most literal sense: it makes a corpse out of him. | |
| From: Simone Weil (The Iliad or the Poem of Force [1940], p.183) | |
| A reaction: She celebrates The Iliad as the great examination of force in human affairs. I have felt that sense of reduction to a thing whenever anyone above me in the hierarchy has arbitrarily exerted their power over me. |
| 23813 | Only people who understand force, and don't respect it, are capable of justice [Weil] |
| Full Idea: Only he who has measured the dominion of force, and knows how not to respect it, is capable of love and justice. | |
| From: Simone Weil (The Iliad or the Poem of Force [1940], p.212) | |
| A reaction: There are, of course, occasions when we are grateful to people who exercise appropriate force on our behalf. I think she was concerned with what is inappropriate. |