13 ideas
| 21554 | Sets always exceed terms, so all the sets must exceed all the sets [Lackey] |
| Full Idea: Cantor proved that the number of sets in a collection of terms is larger than the number of terms. Hence Cantor's Paradox says the number of sets in the collection of all sets must be larger than the number of sets in the collection of all sets. | |
| From: Douglas Lackey (Intros to Russell's 'Essays in Analysis' [1973], p.127) | |
| A reaction: The sets must count as terms in the next iteration, but that is a normal application of the Power Set axiom. |
| 21553 | It seems that the ordinal number of all the ordinals must be bigger than itself [Lackey] |
| Full Idea: The ordinal series is well-ordered and thus has an ordinal number, and a series of ordinals to a given ordinal exceeds that ordinal by 1. So the series of all ordinals has an ordinal number that exceeds its own ordinal number by 1. | |
| From: Douglas Lackey (Intros to Russell's 'Essays in Analysis' [1973], p.127) | |
| A reaction: Formulated by Burali-Forti in 1897. |
| 17818 | How many? must first partition an aggregate into sets, and then logic fixes its number [Yourgrau] |
| Full Idea: We want to know How many what? You must first partition an aggregate into parts relevant to the question, where no partition is privileged. How the partitioned set is to be numbered is bound up with its unique members, and follows from logic alone. | |
| From: Palle Yourgrau (Sets, Aggregates and Numbers [1985], 'New Problem') | |
| A reaction: [Compressed wording of Yourgrau's summary of Frege's 'relativity argument'] Concepts do the partitioning. Yourgau says this fails, because the same argument applies to the sets themselves, as well as to the original aggregates. |
| 17822 | Nothing is 'intrinsically' numbered [Yourgrau] |
| Full Idea: Nothing at all is 'intrinsically' numbered. | |
| From: Palle Yourgrau (Sets, Aggregates and Numbers [1985], 'What the') | |
| A reaction: Once you are faced with distinct 'objects' of some sort, they can play the role of 'unit' in counting, so his challenge is that nothing is 'intrinsically' an object, which is the nihilism explored by Unger, Van Inwagen and Merricks. Aristotle disagrees... |
| 17817 | Defining 'three' as the principle of collection or property of threes explains set theory definitions [Yourgrau] |
| Full Idea: The Frege-Maddy definition of number (as the 'property' of being-three) explains why the definitions of Von Neumann, Zermelo and others work, by giving the 'principle of collection' that ties together all threes. | |
| From: Palle Yourgrau (Sets, Aggregates and Numbers [1985], 'A Fregean') | |
| A reaction: [compressed two or three sentences] I am strongly in favour of the best definition being the one which explains the target, rather than just pinning it down. I take this to be Aristotle's view. |
| 17815 | We can't use sets as foundations for mathematics if we must await results from the upper reaches [Yourgrau] |
| Full Idea: Sets could hardly serve as a foundation for number theory if we had to await detailed results in the upper reaches of the edifice before we could make our first move. | |
| From: Palle Yourgrau (Sets, Aggregates and Numbers [1985], 'Two') |
| 17821 | You can ask all sorts of numerical questions about any one given set [Yourgrau] |
| Full Idea: We can address a set with any question at all that admits of a numerical reply. Thus we can ask of {Carter, Reagan} 'How many feet do the members have?'. | |
| From: Palle Yourgrau (Sets, Aggregates and Numbers [1985], 'On Numbering') | |
| A reaction: This is his objection to the Fregean idea that once you have fixed the members of a set, you have thereby fixed the unique number that belongs with the set. |
| 19513 | A contextualist coherentist will say that how strongly a justification must cohere depends on context [DeRose] |
| Full Idea: If you are a coherentist and a contextualist, you'll probably want to hold that how strongly beliefs must cohere with one another in order to count as knowledge (if they are true), or to count as justified, is a contextually variable matter. | |
| From: Keith DeRose (The Case for Contextualism [2009], 1.09) | |
| A reaction: How exciting! He's talking about ME! Context might not only dictate the strength of the coherence, but also the range of beliefs involved. In fact all of Thagard's criteria of coherence may be subject to contextual variation. |
| 19514 | Classical invariantism combines fixed truth-conditions with variable assertability standards [DeRose] |
| Full Idea: The great rival to contextualism is classical 'invariantism' - invariantism about the truth-conditions [for knowing], combined with variable standards for warranted assertability. | |
| From: Keith DeRose (The Case for Contextualism [2009], 1.12) | |
| A reaction: That is, I take it, that we might want to assert that someone 'knows' something, when the truth is that they don't. That is, either you know or you don't, but we can bend the rules as to whether we say you know. I take this view to be false. |
| 19515 | We can make contextualism more precise, by specifying the discrimination needed each time [DeRose] |
| Full Idea: We might make the basic contextualist schema more precise ...by saying the change in content will consist in a change in the range of relevant alternatives. Higher standards would discriminate from a broader range of alternatives. | |
| From: Keith DeRose (The Case for Contextualism [2009], 1.14) | |
| A reaction: This would handle the 'fake barn' and 'disguised zebra' examples, by saying lower standards do not expect such discriminations. The zebra case has a lower standard than the barn case (because fake barns are the norm here). |
| 19510 | In some contexts there is little more to knowledge than true belief. [DeRose] |
| Full Idea: I'm inclined to accept that in certain contexts the standards for knowledge are so low that little more than true belief is required. | |
| From: Keith DeRose (The Case for Contextualism [2009], 1.6) | |
| A reaction: DeRose emphasises that 'a little more' is needed, rather than none. The example given is where 'he knew that p' means little more than 'the information that p was available to him' (in a political scandal). |
| 19516 | Contextualists worry about scepticism, but they should focus on the use of 'know' in ordinary speech [DeRose] |
| Full Idea: While skepticism has drawn much of the attention of contextualists, support for contextualism should also - and perhaps primarily - be looked for in how 'knows' is utilised in non-philosophical conversation. | |
| From: Keith DeRose (The Case for Contextualism [2009], 1016) | |
| A reaction: Contextualists say scepticism is just raising the standards absurdly high. I take it that the ordinary use of the word 'know' is obviously highly contextual, and so varied that I don't see how philosophers could 'regiment' it into invariant form. |
| 19511 | If contextualism is about knowledge attribution, rather than knowledge, then it is philosophy of language [DeRose] |
| Full Idea: Maybe contextualism isn't a theory about knowledge at all, but about knowledge attributions. As such, it is not a piece of epistemology at all, but of philosophy of language. | |
| From: Keith DeRose (The Case for Contextualism [2009], 1.7) | |
| A reaction: DeRose takes this view to be wrong. At the very least this will have to include self-attributions, by the supposed knower, because I might say 'I know that p', meaning 'but only in this rather low-standard context'. |