9 ideas
| 21336 | Crates lived in poverty, and treated his whole life as a joke [Crates of Thebes, by Plutarch] |
| Full Idea: Crates, with his bag and threadbare cloak, spent his whole life laughing and joking as though he were on holiday. | |
| From: report of Crates (Theb) (fragments/reports [c.325 BCE]) by Plutarch - 30: Quiet of Mind 266e | |
| A reaction: Crates sounds a little less alarming than Diogenes, while living a similar life. Was Crates the first ancestor of post-modernism? |
| 1767 | Everyone should study philosophy until they see all people in the same light [Crates of Thebes, by Diog. Laertius] |
| Full Idea: A man should study philosophy up to the point of looking on generals and donkey-drivers in the same light. | |
| From: report of Crates (Theb) (fragments/reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 06.Cr.9 | |
| A reaction: This seems to reject Aristote's idea that some people are clearly superior to others. |
| 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) |
| 6040 | There is no universal goal to human life [Aenesidemus, by Photius] |
| Full Idea: Aenesidemus does not allow either happiness or pleasure or prudence or any other goal held by anyone on the basis of philosophical doctrine as the goal of life; rather, he says that there just is no such thing as a goal which is recognised by all people. | |
| From: report of Aenesidemus (Pyrrhonian Arguments (frags) [c.60 BCE], Bk 8) by 'Photius Bibliotheca' - Aenesidimus (frags) 170b | |
| A reaction: This is probably the dominant modern (post-Darwinian, existentialist) view. Personally I am sympathetic to the Aristotelian view that (to some extent) appropriate goals for life can be inferred from a fairly stable human nature. |