9 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) |
16236 | Maybe our persistence conditions concern bodies, rather than persons [Olson, by Hawley] |
Full Idea: Instead of attributing person-like persistence conditions to bodies, we could attribute body-like persistence conditions to persons, …so human persons are identical with human organisms. | |
From: report of Eric T. Olson (The Human Animal [1997]) by Katherine Hawley - How Things Persist 5.10 | |
A reaction: In the case of pre-birth and advanced senility, Olson thinks we could have the body without the person, so person is a 'phase sortal' of bodies. A good theory, which seems to answer a lot of questions. 'Person' may be an abstraction. |
6669 | For 'animalism', I exist before I became a person, and can continue after it, so I am not a person [Olson, by Lowe] |
Full Idea: According to 'animalism', I existed before I was a person and I may well go one existing for some time after I cease to be a person; hence, I am not essentially a person, but a human organism. | |
From: report of Eric T. Olson (The Human Animal [1997]) by E.J. Lowe - Introduction to the Philosophy of Mind Ch.10 | |
A reaction: There is a very real sense in which an extremely senile person has 'ceased to exist' (e.g. as the person I used to love). On the whole, though, I think that Olson is right, and yet 'person' is an important concept. Neither concept is all-or-nothing. |
21432 | Culture is the struggle to agree what is normal [Gibson,A] |
Full Idea: Culture is the struggle to agree what is normal. | |
From: Andrew Gibson (talk [2018]) | |
A reaction: A nice aphorism. Typically the struggle took place in villages, but has now gone global. The normalities of other cultures are beamed into a remote society, and are frequently unwelcome. |