40 ideas
| 9786 | Philosophers working like teams of scientists is absurd, yet isolation is hard [Cartwright,R] |
| Full Idea: The notion that philosophy can be done cooperatively, in the manner of scientists or engineers engaged in a research project, seems to me absurd. And yet few philosophers can survive in isolation. | |
| From: Richard Cartwright (Intro to 'Philosophical Essays' [1987], xxi) | |
| A reaction: This why Nietzsche said that philosophers were 'rare plants'. |
| 9784 | A false proposition isn't truer because it is part of a coherent system [Cartwright,R] |
| Full Idea: You do not improve the truth value of a false proposition by calling attention to a coherent system of propositions of which it is one. | |
| From: Richard Cartwright (Intro to 'Philosophical Essays' [1987], xi) | |
| A reaction: We need to disentangle the truth-value from the justification here. If it is false, then we can safely assume that is false, but we are struggling to decide whether it is false, and we want all the evidence we can get. Falsehood tends towards incoherence. |
| 13941 | Are the truth-bearers sentences, utterances, ideas, beliefs, judgements, propositions or statements? [Cartwright,R] |
| Full Idea: What is it that is susceptible of truth or falsity? The answers suggested constitute a bewildering variety: sentences, utterances, ideas, beliefs, judgments, propositions, statements. | |
| From: Richard Cartwright (Propositions [1962], 01) | |
| A reaction: Carwright's answer is 'statements', which seem to be the same as propositions. |
| 13942 | Logicians take sentences to be truth-bearers for rigour, rather than for philosophical reasons [Cartwright,R] |
| Full Idea: The current fashion among logicians of taking sentences to be the bearers of truth and falsity indicates less an agreement on philosophical theory than a desire for rigor and smoothness in calculative practice. | |
| From: Richard Cartwright (Propositions [1962], 01) | |
| A reaction: A remark close to my heart. Propositions are rejected first because language offers hope of answers, then because they seem metaphysically odd, and finally because you can't pin them down rigorously. But the blighters won't lie down and die. |
| 10859 | A set is 'well-ordered' if every subset has a first element [Clegg] |
| Full Idea: For a set to be 'well-ordered' it is required that every subset of the set has a first element. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10857 | Set theory made a closer study of infinity possible [Clegg] |
| Full Idea: Set theory made a closer study of infinity possible. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10864 | Any set can always generate a larger set - its powerset, of subsets [Clegg] |
| Full Idea: The idea of the 'power set' means that it is always possible to generate a bigger one using only the elements of that set, namely the set of all its subsets. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.14) |
| 10872 | Extensionality: Two sets are equal if and only if they have the same elements [Clegg] |
| Full Idea: Axiom of Extension: Two sets are equal if and only if they have the same elements. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10875 | Pairing: For any two sets there exists a set to which they both belong [Clegg] |
| Full Idea: Axiom of Pairing: For any two sets there exists a set to which they both belong. So you can make a set out of two other sets. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10876 | Unions: There is a set of all the elements which belong to at least one set in a collection [Clegg] |
| Full Idea: Axiom of Unions: For every collection of sets there exists a set that contains all the elements that belong to at least one of the sets in the collection. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10878 | Infinity: There exists a set of the empty set and the successor of each element [Clegg] |
| Full Idea: Axiom of Infinity: There exists a set containing the empty set and the successor of each of its elements. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: This is rather different from the other axioms because it contains the notion of 'successor', though that can be generated by an ordering procedure. |
| 10877 | Powers: All the subsets of a given set form their own new powerset [Clegg] |
| Full Idea: Axiom of Powers: For each set there exists a collection of sets that contains amongst its elements all the subsets of the given set. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: Obviously this must include the whole of the base set (i.e. not just 'proper' subsets), otherwise the new set would just be a duplicate of the base set. |
| 10879 | Choice: For every set a mechanism will choose one member of any non-empty subset [Clegg] |
| Full Idea: Axiom of Choice: For every set we can provide a mechanism for choosing one member of any non-empty subset of the set. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: This axiom is unusual because it makes the bold claim that such a 'mechanism' can always be found. Cohen showed that this axiom is separate. The tricky bit is choosing from an infinite subset. |
| 10871 | Axiom of Existence: there exists at least one set [Clegg] |
| Full Idea: Axiom of Existence: there exists at least one set. This may be the empty set, but you need to start with something. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10874 | Specification: a condition applied to a set will always produce a new set [Clegg] |
| Full Idea: Axiom of Specification: For every set and every condition, there corresponds a set whose elements are exactly the same as those elements of the original set for which the condition is true. So the concept 'number is even' produces a set from the integers. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) | |
| A reaction: What if the condition won't apply to the set? 'Number is even' presumably won't produce a set if it is applied to a set of non-numbers. |
| 10880 | Mathematics can be 'pure' (unapplied), 'real' (physically grounded); or 'applied' (just applicable) [Clegg] |
| Full Idea: Three views of mathematics: 'pure' mathematics, where it doesn't matter if it could ever have any application; 'real' mathematics, where every concept must be physically grounded; and 'applied' mathematics, using the non-real if the results are real. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.17) | |
| A reaction: Very helpful. No one can deny the activities of 'pure' mathematics, but I think it is undeniable that the origins of the subject are 'real' (rather than platonic). We do economics by pretending there are concepts like the 'average family'. |
| 10861 | Beyond infinity cardinals and ordinals can come apart [Clegg] |
| Full Idea: With ordinary finite numbers ordinals and cardinals are in effect the same, but beyond infinity it is possible for two sets to have the same cardinality but different ordinals. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10860 | An ordinal number is defined by the set that comes before it [Clegg] |
| Full Idea: You can think of an ordinal number as being defined by the set that comes before it, so, in the non-negative integers, ordinal 5 is defined as {0, 1, 2, 3, 4}. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.13) |
| 10854 | Transcendental numbers can't be fitted to finite equations [Clegg] |
| Full Idea: The 'transcendental numbers' are those irrationals that can't be fitted to a suitable finite equation, of which π is far and away the best known. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch. 6) |
| 10858 | By adding an axis of imaginary numbers, we get the useful 'number plane' instead of number line [Clegg] |
| Full Idea: The realisation that brought 'i' into the toolkit of physicists and engineers was that you could extend the 'number line' into a new dimension, with an imaginary number axis at right angles to it. ...We now have a 'number plane'. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.12) |
| 10853 | Either lack of zero made early mathematics geometrical, or the geometrical approach made zero meaningless [Clegg] |
| Full Idea: It is a chicken-and-egg problem, whether the lack of zero forced forced classical mathematicians to rely mostly on a geometric approach to mathematics, or the geometric approach made 0 a meaningless concept, but the two remain strongly tied together. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch. 6) |
| 10866 | Cantor's account of infinities has the shaky foundation of irrational numbers [Clegg] |
| Full Idea: As far as Kronecker was concerned, Cantor had built a whole structure on the irrational numbers, and so that structure had no foundation at all. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10869 | The Continuum Hypothesis is independent of the axioms of set theory [Clegg] |
| Full Idea: Paul Cohen showed that the Continuum Hypothesis is independent of the axioms of set theory. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.15) |
| 10862 | The 'continuum hypothesis' says aleph-one is the cardinality of the reals [Clegg] |
| Full Idea: The 'continuum hypothesis' says that aleph-one is the cardinality of the rational and irrational numbers. | |
| From: Brian Clegg (Infinity: Quest to Think the Unthinkable [2003], Ch.14) |
| 9783 | While no two classes coincide in membership, there are distinct but coextensive attributes [Cartwright,R] |
| Full Idea: Attributes and classes are said to be distinguished by the fact that whereas no two classes coincide in membership, there are supposed to be distinct but coextensive attributes. | |
| From: Richard Cartwright (Classes and Attributes [1967], §2) | |
| A reaction: This spells out the standard problem of renates and cordates, that creatures with hearts and with kidneys are precisely coextensive, but that these properties are different. Cartwright then attacks the distinction. |
| 14961 | Clearly a pipe can survive being taken apart [Cartwright,R] |
| Full Idea: There is at the moment a pipe on my desk. Its stem has been removed but it remains a pipe for all that; otherwise no pipe could survive a thorough cleaning. | |
| From: Richard Cartwright (Scattered Objects [1974], p.175) | |
| A reaction: To say that the pipe survives dismantling is not to say that it is fully a pipe during its dismantled phase. He gives a further example of a book in two volumes. |
| 14962 | Bodies don't becomes scattered by losing small or minor parts [Cartwright,R] |
| Full Idea: If a branch falls from a tree, the tree does not thereby become scattered, and a human body does not become scattered upon loss of a bit of fingernail. | |
| From: Richard Cartwright (Scattered Objects [1974], p.184) | |
| A reaction: This sort of observation draws me towards essentialism. A body is scattered if you divide it in a major way, but not if you separate off a minor part. It isn't just a matter of size, or even function. We have broader idea of what is essential. |
| 13952 | Essentialism says some of a thing's properties are necessary, and could not be absent [Cartwright,R] |
| Full Idea: Essentialism, as I shall understand it, is the doctrine that among the attributes of a thing some are essential, others merely accidental. Its essential attributes are those it has necessarily, those it could not have lacked. | |
| From: Richard Cartwright (Some Remarks on Essentialism [1968], p.149) | |
| A reaction: The problem with this, which Cartwright does not address, is that trivial and gerrymandered properties (such as having self-identity, or being 'such that 2+2=4') seem to be necessarily, but don't seem to constitute the essence of a thing. |
| 13954 | The difficulty in essentialism is deciding the grounds for rating an attribute as essential [Cartwright,R] |
| Full Idea: I see no reason for thinking essentialism unintelligible, but a chief perplexity is the obscurity of the grounds on which ratings of attributes as essential or accidental are to be made. | |
| From: Richard Cartwright (Some Remarks on Essentialism [1968], p.158) | |
| A reaction: In that case some of us younger philosophers will have to roll up our sleeves and tease out the grounds for essentialism, starting with Aristotle and Leibniz, and ending with the successes of modern science. |
| 13955 | Essentialism is said to be unintelligible, because relative, if necessary truths are all analytic [Cartwright,R] |
| Full Idea: Apparently those who think essentialism unintelligible see support for their position in the doctrine that necessary truths are all analytic. Only relative to some mode of designation does it make sense to speak of an object as necessarily this or that. | |
| From: Richard Cartwright (Some Remarks on Essentialism [1968], p.158) | |
| A reaction: He has in mind Quine and his mathematician-cyclist (Idea 8482). Personally I have no problems with the example. No one is essentially a cyclist - that isn't what essence is. Two-legged people can be cyclists. |
| 13953 | An act of ostension doesn't seem to need a 'sort' of thing, even of a very broad kind [Cartwright,R] |
| Full Idea: For an ostension to be successful it is surely not necessary that I gather what sort of object it is you have indicated, such as being a horse or a zebra. I may even gather which thing you have indicated without knowing that it is a mammal or even alive. | |
| From: Richard Cartwright (Some Remarks on Essentialism [1968], p.157) | |
| A reaction: This nicely articulates the objection I have always felt to Geach's relative identity. 'Oh my God, what the hell is THAT???' is probably going to be a successful act of verbal reference, even while explicitly denying all knowledge of sortals. |
| 13945 | A token isn't a unique occurrence, as the case of a word or a number shows [Cartwright,R] |
| Full Idea: We cannot take a token of a word to be an occurrence of it. Suppose there is exactly one occurrence of the word 'etherized' in the whole of English poetry? Exactly one 'token'? This sort of occurrence is like the occurrence of a number in a sequence. | |
| From: Richard Cartwright (Propositions [1962], Add 2) | |
| A reaction: This remark is in an addendum to his paper, criticising his own lax use of the idea of 'token' in the actual paper. The example nicely shows that the type/token distinction isn't neat and tidy - though I consider it very useful. |
| 20653 | Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson] |
| Full Idea: There are six 'reductive levels' in science: social groups, (multicellular) living things, cells, molecules, atoms, and elementary particles. | |
| From: report of H.Putnam/P.Oppenheim (Unity of Science as a Working Hypothesis [1958]) by Peter Watson - Convergence 10 'Intro' | |
| A reaction: I have the impression that fields are seen as more fundamental that elementary particles. What is the status of the 'laws' that are supposed to govern these things? What is the status of space and time within this picture? |
| 13948 | For any statement, there is no one meaning which any sentence asserting it must have [Cartwright,R] |
| Full Idea: It does have to be acknowledged, I think, that every statement whatever is such that there is no one meaning which any sentence used to assert it must have. | |
| From: Richard Cartwright (Propositions [1962], 11) | |
| A reaction: This feels to me like a Gricean move - that what we are really interested in is communicating one mental state to another mental state, and there are all sorts of tools that can do that one job. |
| 13950 | People don't assert the meaning of the words they utter [Cartwright,R] |
| Full Idea: No one ever asserts the meaning of the words he utters. | |
| From: Richard Cartwright (Propositions [1962], 12) | |
| A reaction: Cartwright is using this point to drive a wedge between sentence meaning and the assertion made by the utterance. Hence he defends propositions. Presumably people utilise word-meanings, rather than asserting them. Meanings (not words) are tools. |
| 13944 | We can pull apart assertion from utterance, and the action, the event and the subject-matter for each [Cartwright,R] |
| Full Idea: We need to distinguish 1) what is asserted, 2) that assertion, 3) asserting something, 4) what is predicated, 5) what is uttered, 6) that utterance, 7) uttering something, 8) the utterance token, and 9) the meaning. | |
| From: Richard Cartwright (Propositions [1962], 05-06) | |
| A reaction: [summary of his overall analysis in the paper] It is amazingly hard to offer a critical assessment of this sort of analysis, but it gives you a foot in the door for thinking about the issues with increasing clarity. |
| 13947 | 'It's raining' makes a different assertion on different occasions, but its meaning remains the same [Cartwright,R] |
| Full Idea: A person who utters 'It's raining' one day does not normally make the same statement as one who utters it the next. But these variations are not accompanied by corresponding changes of meaning. The words 'It's raining' retain the same meaning throughout. | |
| From: Richard Cartwright (Propositions [1962], 10) | |
| A reaction: This is important, because it shows that a proposition is not just the mental shadow behind a sentence, or a mental shadow awaiting a sentence. Unlike a sentence, a proposition can (and possibly must) include its own context. Very interesting! |
| 13943 | We can attribute 'true' and 'false' to whatever it was that was said [Cartwright,R] |
| Full Idea: We do sometimes say of something to which we have referred that it is true (or false). Are we not ordinarily doing just this when we utter such sentences as 'That's true' and 'What he said was false'? | |
| From: Richard Cartwright (Propositions [1962], 03) | |
| A reaction: This supports propositions, but doesn't clinch the matter. One could interpret this phenomenon as always being (implicitly) the reference of one sentence to another. However, I remember what he said, but I can't remember how he said it. |
| 13946 | To assert that p, it is neither necessary nor sufficient to utter some particular words [Cartwright,R] |
| Full Idea: In order to assert that p it is not necessary to utter exactly those words. ...Clearly, also, in order to assert that p, it is not sufficient to utter the words that were actually uttered. | |
| From: Richard Cartwright (Propositions [1962], 07) | |
| A reaction: I take the first point to be completely obvious (you can assert one thing with various wordings), and the second seems right after a little thought (the words could be vague, ambiguous, inaccurate, contextual) |
| 13951 | Assertions, unlike sentence meanings, can be accurate, probable, exaggerated, false.... [Cartwright,R] |
| Full Idea: Whereas what is asserted can be said to be accurate, exaggerated, unfounded, overdrawn, probable, improbable, plausible, true, or false, none of these can be said of the meaning of a sentence. | |
| From: Richard Cartwright (Propositions [1962], 12) | |
| A reaction: That fairly firmly kicks into touch the idea that the assertion is the same as the meaning of the sentence. |