9 ideas
| 17833 | The first-order ZF axiomatisation is highly non-categorical [Hallett,M] |
| Full Idea: The first-order Sermelo-Fraenkel axiomatisation is highly non-categorical. | |
| From: Michael Hallett (Introduction to Zermelo's 1930 paper [1996], p.1213) |
| 17834 | Non-categoricity reveals a sort of incompleteness, with sets existing that the axioms don't reveal [Hallett,M] |
| Full Idea: The non-categoricity of the axioms which Zermelo demonstrates reveals an incompleteness of a sort, ....for this seems to show that there will always be a set (indeed, an unending sequence) that the basic axioms are incapable of revealing to be sets. | |
| From: Michael Hallett (Introduction to Zermelo's 1930 paper [1996], p.1215) | |
| A reaction: Hallett says the incompleteness concerning Zermelo was the (transfinitely) indefinite iterability of the power set operation (which is what drives the 'iterative conception' of sets). |
| 17837 | Zermelo allows ur-elements, to enable the widespread application of set-theory [Hallett,M] |
| Full Idea: Unlike earlier writers (such as Fraenkel), Zermelo clearly allows that there might be ur-elements (that is, objects other than the empty set, which have no members). Indeed he sees in this the possibility of widespread application of set-theory. | |
| From: Michael Hallett (Introduction to Zermelo's 1930 paper [1996], p.1217) |
| 17836 | The General Continuum Hypothesis and its negation are both consistent with ZF [Hallett,M] |
| Full Idea: In 1938, Gödel showed that ZF plus the General Continuum Hypothesis is consistent if ZF is. Cohen showed that ZF and not-GCH is also consistent if ZF is, which finally shows that neither GCH nor ¬GCH can be proved from ZF itself. | |
| From: Michael Hallett (Introduction to Zermelo's 1930 paper [1996], p.1217) |
| 22626 | Process philosophy insists that processes are not inferior in being to substances [Rescher] |
| Full Idea: Process philosophy diametrically opposes the view that denies processes or downgrades them in the order of being or of understanding by subordinating them to substantial things. | |
| From: Nicholas Rescher (Process Metaphysics [1996]), quoted by R.D. Ingthorsson - A Powerful Particulars View of Causation 7 | |
| A reaction: [No page cited - nr start?] Ingthorsson quotes this in order to challenge it, and says that substances are also processes, because change is essential to them. |
| 10650 | In the military, persons are parts of parts of large units, but not parts of those large units [Rescher] |
| Full Idea: In military usage, persons can be parts of small units, and small units parts of large ones; but persons are never parts of large units. | |
| From: Nicholas Rescher (Axioms for the Part Relation [1955]), quoted by Achille Varzi - Mereology 2.1 | |
| A reaction: This much-cited objection to the transitivity of the 'part' relation seems very odd. There could hardly be an army or a regiment if there weren't soldiers to make up parts of it. |
| 8836 | Must all justification be inferential? [Ginet] |
| Full Idea: The infinitist view of justification holds that every justification must be inferential: no other kind of justification is possible. | |
| From: Carl Ginet (Infinitism not solution to regress problem [2005], p.141) | |
| A reaction: This is the key question in discussing whether justification is foundational. I'm not sure whether 'inference' is the best word when something is evidence for something else. I am inclined to think that only propositions can be reasons. |
| 8837 | Inference cannot originate justification, it can only transfer it from premises to conclusion [Ginet] |
| Full Idea: Inference cannot originate justification, it can only transfer it from premises to conclusion. And so it cannot be that, if there actually occurs justification, it is all inferential. | |
| From: Carl Ginet (Infinitism not solution to regress problem [2005], p.148) | |
| A reaction: The idea that justification must have an 'origin' seems to beg the question. I take Klein's inifinitism to be a version of coherence, where the accumulation of good reasons adds up to justification. It is not purely inferential. |
| 20365 | We only see points in motion, and thereby infer movement [Rescher] |
| Full Idea: We perceive motion only as isolated points, and then infer it without actually seeing it. | |
| From: Nicholas Rescher (Scepticism [1980], §112) | |
| A reaction: Note how writing suddenly becomes readable as you slow down on entering a railway station. Is that points suddenly becoming unified? This is an empiricist endorsement of Russell's 'at-at' account of motion. |