12 ideas
9967 | 'Impure' sets have a concrete member, while 'pure' (abstract) sets do not [Jubien] |
Full Idea: Any set with a concrete member is 'impure'. 'Pure' sets are those that are not impure, and are paradigm cases of abstract entities, such as the sort of sets apparently dealt with in Zermelo-Fraenkel (ZF) set theory. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.116) | |
A reaction: [I am unclear whether Jubien is introducing this distinction] This seems crucial in accounts of mathematics. On the one had arithmetic can be built from Millian pebbles, giving impure sets, while logicists build it from pure sets. |
9968 | A model is 'fundamental' if it contains only concrete entities [Jubien] |
Full Idea: A first-order model can be viewed as a kind of ordered set, and if the domain of the model contains only concrete entities then it is a 'fundamental' model. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.117) | |
A reaction: An important idea. Fundamental models are where the world of logic connects with the physical world. Any account of relationship between fundamental models and more abstract ones tells us how thought links to world. |
9965 | There couldn't just be one number, such as 17 [Jubien] |
Full Idea: It makes no sense to suppose there might be just one natural number, say seventeen. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.113) | |
A reaction: Hm. Not convinced. If numbers are essentially patterns, we might only have the number 'twelve', because we had built our religion around anything which exhibited that form (in any of its various arrangements). Nice point, though. |
9966 | The subject-matter of (pure) mathematics is abstract structure [Jubien] |
Full Idea: The subject-matter of (pure) mathematics is abstract structure per se. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.115) | |
A reaction: This is the Structuralist idea beginning to take shape after Benacerraf's launching of it. Note that Jubien gets there by his rejection of platonism, whereas some structuralist have given a platonist interpretation of structure. |
9964 | Since mathematical objects are essentially relational, they can't be picked out on their own [Jubien] |
Full Idea: The essential properties of mathematical entities seem to be relational, ...so we make no progress unless we can pick out some mathematical entities wihout presupposing other entities already picked out. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.112) | |
A reaction: [compressed] Jubien is a good critic of platonism. He has identified the problem with Frege's metaphor of a 'borehole', where we discover delightful new properties of numbers simply by reaching them. |
9963 | If we all intuited mathematical objects, platonism would be agreed [Jubien] |
Full Idea: If the intuition of mathematical objects were general, there would be no real debate over platonism. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.111) | |
A reaction: It is particularly perplexing when Gödel says that his perception of them is just like sight or smell, since I have no such perception. How do you individuate very large numbers, or irrational numbers, apart from writing down numerals? |
9962 | How can pure abstract entities give models to serve as interpretations? [Jubien] |
Full Idea: I am unable to see how the mere existence of pure abstract entities enables us to concoct appropriate models to serve as interpretations. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.111) | |
A reaction: Nice question. It is always assumed that once we have platonic realm, that everything else follows. Even if we are able to grasp the objects, despite their causal inertness, we still have to discern innumerable relations between them. |
9969 | The empty set is the purest abstract object [Jubien] |
Full Idea: The empty set is the pure abstract object par excellence. | |
From: Michael Jubien (Ontology and Mathematical Truth [1977], p.118 n8) | |
A reaction: So a really good PhD on the empty set could crack the whole nature of reality. Get to work, whoever you are! |
22419 | 'I' is a subject in 'I am in pain' and an object in 'I am bleeding' [Wittgenstein, by McGinn] |
Full Idea: 'I' is used as a subject in 'I am in pain', ....and used as an object in 'I am bleeding'. | |
From: report of Ludwig Wittgenstein (The Blue and Brown Notebooks [1936], pp. 66-7) by Colin McGinn - Subjective View: sec qualities and indexicals 4 | |
A reaction: How about 'my wound is painful'? Does that have the logical form of a conversation? This idea is incorrect. Shoemaker (1968) suggests that the subjective use is immune to error, unlike the object use. |
6318 | The doctrine of indeterminacy of translation seems implied by the later Wittgenstein [Wittgenstein, by Quine] |
Full Idea: Perhaps the doctrine of indeterminacy of translation will have little air of paradox for readers familiar with Wittgenstein's latter-day remarks on meaning. | |
From: report of Ludwig Wittgenstein (The Blue and Brown Notebooks [1936], II.§16 n) by Willard Quine - Word and Object II.§16 n | |
A reaction: This may be right, and I am inclined to link the names of Wittgenstein and Quine among those who led philosophy up a relativistic and sceptical cul-de-sac for many years. You can think too hard, you know. |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
Full Idea: Archelaus was the first person to say that the universe is boundless. | |
From: report of Archelaus (fragments/reports [c.450 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 02.Ar.3 |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |
Full Idea: Archelaus wrote that life on Earth began in a primeval slime. | |
From: report of Archelaus (fragments/reports [c.450 BCE]) by Malcolm Schofield - Archelaus | |
A reaction: This sounds like a fairly clearcut assertion of the production of life by evolution. Darwin's contribution was to propose the mechanism for achieving it. We should honour the name of Archelaus for this idea. |