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) |
| 19696 | There are reasons 'for which' a belief is held, reasons 'why' it is believed, and reasons 'to' believe it [Neta] |
| Full Idea: We must distinguish between something's being a 'reason for which' a creature believes something, and its being a 'reason why' a creature believes something. ...We must also distinguish a 'reason for which' from a 'reason to' believe something. | |
| From: Ram Neta (The Basing Relation [2011], Intro) | |
| A reaction: He doesn't spell the distinctions out clearly. I take it that 'for which' is my personal justification, 'why' is the dodgy prejudices that cause my belief. and 'to' is some actual good reasons, of which I may be unaware. |
| 19697 | The basing relation of a reason to a belief should both support and explain the belief [Neta] |
| Full Idea: A reason has a 'basing relation' with a belief if it (i) rationally supports holding the belief, and (ii) explains why the belief is held. | |
| From: Ram Neta (The Basing Relation [2011], Intro) | |
| A reaction: Presumably a false reason would fit this account. Why not talk of 'grounding', or is that word now reserved for metaphysics? If I hypnotise you into a belief, would my hypnotic power be the basing reason? Fits (ii), but not (i). |
| 19590 | Empiricists are passive thinkers, given their philosophy by the external world and fate [Novalis] |
| Full Idea: An empiricist is one whose way of thinking is an effect of the external world and of fate - the passive thinker - to whom his philosophy is given. | |
| From: Novalis (Teplitz Fragments [1798], 33) | |
| A reaction: Novalis goes on to enthuse about 'magical idealism', so he rejects empiricism. This is an early attack on the Myth of the Given, found in Sellars and McDowell. |