34 ideas
| 10170 | While true-in-a-model seems relative, true-in-all-models seems not to be [Reck/Price] |
| Full Idea: While truth can be defined in a relative way, as truth in one particular model, a non-relative notion of truth is implied, as truth in all models. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4) | |
| A reaction: [The article is actually discussing arithmetic] This idea strikes me as extremely important. True-in-all-models is usually taken to be tautological, but it does seem to give a more universal notion of truth. See semantic truth, Tarski, Davidson etc etc. |
| 10166 | ZFC set theory has only 'pure' sets, without 'urelements' [Reck/Price] |
| Full Idea: In standard ZFC ('Zermelo-Fraenkel with Choice') set theory we deal merely with pure sets, not with additional urelements. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2) | |
| A reaction: The 'urelements' would the actual objects that are members of the sets, be they physical or abstract. This idea is crucial to understanding philosophy of mathematics, and especially logicism. Must the sets exist, just as the urelements do? |
| 10175 | Three types of variable in second-order logic, for objects, functions, and predicates/sets [Reck/Price] |
| Full Idea: In second-order logic there are three kinds of variables, for objects, for functions, and for predicates or sets. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5) | |
| A reaction: It is interesting that a predicate seems to be the same as a set, which begs rather a lot of questions. For those who dislike second-order logic, there seems nothing instrinsically wicked in having variables ranging over innumerable multi-order types. |
| 10165 | 'Analysis' is the theory of the real numbers [Reck/Price] |
| Full Idea: 'Analysis' is the theory of the real numbers. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2) | |
| A reaction: 'Analysis' began with the infinitesimal calculus, which later built on the concept of 'limit'. A continuum of numbers seems to be required to make that work. |
| 10174 | Mereological arithmetic needs infinite objects, and function definitions [Reck/Price] |
| Full Idea: The difficulties for a nominalistic mereological approach to arithmetic is that an infinity of physical objects are needed (space-time points? strokes?), and it must define functions, such as 'successor'. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4) | |
| A reaction: Many ontologically austere accounts of arithmetic are faced with the problem of infinity. The obvious non-platonist response seems to be a modal or if-then approach. To postulate infinite abstract or physical entities so that we can add 3 and 2 is mad. |
| 10164 | Peano Arithmetic can have three second-order axioms, plus '1' and 'successor' [Reck/Price] |
| Full Idea: A common formulation of Peano Arithmetic uses 2nd-order logic, the constant '1', and a one-place function 's' ('successor'). Three axioms then give '1 is not a successor', 'different numbers have different successors', and induction. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2) | |
| A reaction: This is 'second-order' Peano Arithmetic, though it is at least as common to formulate in first-order terms (only quantifying over objects, not over properties - as is done here in the induction axiom). I like the use of '1' as basic instead of '0'! |
| 10172 | Set-theory gives a unified and an explicit basis for mathematics [Reck/Price] |
| Full Idea: The merits of basing an account of mathematics on set theory are that it allows for a comprehensive unified treatment of many otherwise separate branches of mathematics, and that all assumption, including existence, are explicit in the axioms. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4) | |
| A reaction: I am forming the impression that set-theory provides one rather good model (maybe the best available) for mathematics, but that doesn't mean that mathematics is set-theory. The best map of a landscape isn't a landscape. |
| 10167 | Structuralism emerged from abstract algebra, axioms, and set theory and its structures [Reck/Price] |
| Full Idea: Structuralism has emerged from the development of abstract algebra (such as group theory), the creation of axiom systems, the introduction of set theory, and Bourbaki's encyclopaedic survey of set theoretic structures. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2) | |
| A reaction: In other words, mathematics has gradually risen from one level of abstraction to the next, so that mathematical entities like points and numbers receive less and less attention, with relationships becoming more prominent. |
| 10169 | Relativist Structuralism just stipulates one successful model as its arithmetic [Reck/Price] |
| Full Idea: Relativist Structuralism simply picks one particular model of axiomatised arithmetic (i.e. one particular interpretation that satisfies the axioms), and then stipulates what the elements, functions and quantifiers refer to. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4) | |
| A reaction: The point is that a successful model can be offered, and it doesn't matter which one, like having any sort of aeroplane, as long as it flies. I don't find this approach congenial, though having a model is good. What is the essence of flight? |
| 10179 | There are 'particular' structures, and 'universal' structures (what the former have in common) [Reck/Price] |
| Full Idea: The term 'structure' has two uses in the literature, what can be called 'particular structures' (which are particular relational systems), but also what can be called 'universal structures' - what particular systems share, or what they instantiate. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §6) | |
| A reaction: This is a very helpful distinction, because it clarifies why (rather to my surprise) some structuralists turn out to be platonists in a new guise. Personal my interest in structuralism has been anti-platonist from the start. |
| 10181 | Pattern Structuralism studies what isomorphic arithmetic models have in common [Reck/Price] |
| Full Idea: According to 'pattern' structuralism, what we study are not the various particular isomorphic models of arithmetic, but something in addition to them: a corresponding pattern. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §7) | |
| A reaction: Put like that, we have to feel a temptation to wield Ockham's Razor. It's bad enough trying to give the structure of all the isomorphic models, without seeking an even more abstract account of underlying patterns. But patterns connect to minds.. |
| 10182 | There are Formalist, Relativist, Universalist and Pattern structuralism [Reck/Price] |
| Full Idea: There are four main variants of structuralism in the philosophy of mathematics - formalist structuralism, relativist structuralism, universalist structuralism (with modal variants), and pattern structuralism. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §9) | |
| A reaction: I'm not sure where Chihara's later book fits into this, though it is at the nominalist end of the spectrum. Shapiro and Resnik do patterns (the latter more loosely); Hellman does modal universalism; Quine does the relativist version. Dedekind? |
| 10168 | Formalist Structuralism says the ontology is vacuous, or formal, or inference relations [Reck/Price] |
| Full Idea: Formalist Structuralism endorses structural methodology in mathematics, but rejects semantic and metaphysical problems as either meaningless, or purely formal, or as inference relations. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §3) | |
| A reaction: [very compressed] I find the third option fairly congenial, certainly in preference to rather platonist accounts of structuralism. One still needs to distinguish the mathematical from the non-mathematical in the inference relations. |
| 10178 | Maybe we should talk of an infinity of 'possible' objects, to avoid arithmetic being vacuous [Reck/Price] |
| Full Idea: It is tempting to take a modal turn, and quantify over all possible objects, because if there are only a finite number of actual objects, then there are no models (of the right sort) for Peano Arithmetic, and arithmetic is vacuously true. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5) | |
| A reaction: [compressed; Geoffrey Hellman is the chief champion of this view] The article asks whether we are not still left with the puzzle of whether infinitely many objects are possible, instead of existent. |
| 10176 | Universalist Structuralism is based on generalised if-then claims, not one particular model [Reck/Price] |
| Full Idea: Universalist Structuralism is a semantic thesis, that an arithmetical statement asserts a universal if-then statement. We build an if-then statement (using quantifiers) into the structure, and we generalise away from any one particular model. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5) | |
| A reaction: There remains the question of what is distinctively mathematical about the highly generalised network of inferences that is being described. Presumable the axioms capture that, but why those particular axioms? Russell is cited as an originator. |
| 10177 | Universalist Structuralism eliminates the base element, as a variable, which is then quantified out [Reck/Price] |
| Full Idea: Universalist Structuralism is eliminativist about abstract objects, in a distinctive form. Instead of treating the base element (say '1') as an ambiguous referring expression (the Relativist approach), it is a variable which is quantified out. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5) | |
| A reaction: I am a temperamental eliminativist on this front (and most others) so this is tempting. I am also in love with the concept of a 'variable', which I take to be utterly fundamental to all conceptual thought, even in animals, and not just a trick of algebra. |
| 10171 | The existence of an infinite set is assumed by Relativist Structuralism [Reck/Price] |
| Full Idea: Relativist Structuralism must first assume the existence of an infinite set, otherwise there would be no model to pick, and arithmetical terms would have no reference. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4) | |
| A reaction: See Idea 10169 for Relativist Structuralism. They point out that ZFC has an Axiom of Infinity. |
| 10173 | A nominalist might avoid abstract objects by just appealing to mereological sums [Reck/Price] |
| Full Idea: One way for a nominalist to reject appeal to all abstract objects, including sets, is to only appeal to nominalistically acceptable objects, including mereological sums. | |
| From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4) | |
| A reaction: I'm suddenly thinking that this looks very interesting and might be the way to go. The issue seems to be whether mereological sums should be seen as constrained by nature, or whether they are unrestricted. See Mereology in Ontology...|Intrinsic Identity. |
| 21233 | The beautiful is whatever it is intrinsically good to admire [Moore,GE] |
| Full Idea: The beautiful should be defined as that of which the admiring contemplation is good in itself. | |
| From: G.E. Moore (Principia Ethica [1903], p.210), quoted by Graham Farmelo - The Strangest Man | |
| A reaction: To work, this definition must exclude anything else which it is intrinsically good to admire. Good deeds obviously qualify for that, so good deeds must be intrinsically beautiful (which would be agreed by ancient Greeks). We can't ask WHY it is good! |
| 8039 | Moore tries to show that 'good' is indefinable, but doesn't understand what a definition is [MacIntyre on Moore,GE] |
| Full Idea: Moore tries to show that 'good' is indefinable by relying on a bad dictionary definition of 'definition'. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Alasdair MacIntyre - After Virtue: a Study in Moral Theory Ch.2 | |
| A reaction: An interesting remark, with no further explanation offered. If Moore has this problem, then Plato had it too (see Idea 3032). I would have thought that any definition MacIntyre could offer would either be naturalistic, or tautological. |
| 22151 | The Open Question argument leads to anti-realism and the fact-value distinction [Boulter on Moore,GE] |
| Full Idea: Moore's Open Question argument led, however unintentionally, to the rise of anti-realism in meta-ethics (which leads to distinguishing values from facts). | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Stephen Boulter - Why Medieval Philosophy Matters 4 | |
| A reaction: I presume that Moore proves that the Good is not natural, and after that no one knows what it is, so it seems to be arbitrary or non-existent (rather than the platonic fact that Moore had hoped for). I vote for naturalistic ethics. |
| 11056 | The naturalistic fallacy claims that natural qualties can define 'good' [Moore,GE] |
| Full Idea: The naturalistic fallacy ..consists in the contention that good means nothing but some simple or complex notion, that can be defined in terms of natural qualities. | |
| From: G.E. Moore (Principia Ethica [1903], §044) | |
| A reaction: Presumably aimed at those who think morality is pleasure and pain. We could hardly attribute morality to non-human qualities. I connect morality to human deliberative functions. |
| 8033 | Moore cannot show why something being good gives us a reason for action [MacIntyre on Moore,GE] |
| Full Idea: Moore's account leaves it entirely unexplained and inexplicable why something's being good should ever furnish us with a reason for action. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Alasdair MacIntyre - A Short History of Ethics Ch.18 | |
| A reaction: The same objection can be raised to Plato's Form of the Good, but Plato's answer seems to be that the Good is partly a rational entity, and partly that the Good just has a natural magnetism that makes it quasi-religious. |
| 8032 | Can learning to recognise a good friend help us to recognise a good watch? [MacIntyre on Moore,GE] |
| Full Idea: How could having learned to recognize a good friend help us to recognize a good watch? Yet is Moore is right, the same simple property is present in both cases? | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Alasdair MacIntyre - A Short History of Ethics Ch.18 | |
| A reaction: It begins to look as if what they have in common is just that they both make you feel good. However, I like the Aristotelian idea that they both function succesfully, one as a timekeeper, the other as a citizen or companion. |
| 11050 | Moore's combination of antinaturalism with strong supervenience on the natural is incoherent [Hanna on Moore,GE] |
| Full Idea: Moore incoherently combines his antinaturalism with the thesis that intrinsic-value properties are logically strongly supervenient on (or explanatorily reducible to) natural facts. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by Robert Hanna - Rationality and Logic Ch.1 | |
| A reaction: I take this to be Moore fighting shy of the strongly Platonist view of values which his arguments all seemed to imply. |
| 23726 | Despite Moore's caution, non-naturalists incline towards intuitionism [Moore,GE, by Smith,M] |
| Full Idea: Although Moore was reluctant to adopt it, the epistemology the non-naturalists tended to favour was intuitionism. | |
| From: report of G.E. Moore (Principia Ethica [1903]) by Michael Smith - The Moral Problem 2.2 | |
| A reaction: Moore was presumably reluctant because intuitionism had been heavily criticised in the past for its inability to settle moral disputes. But if you insist that goodness is outside nature, what other means of knowing it is available? Reason? |
| 18676 | We should ask what we would judge to be good if it existed in absolute isolation [Moore,GE] |
| Full Idea: It is necessary to consider what things are such that, if they existed by themselves, in absolute isolation, we should yet judge their existence to be good. | |
| From: G.E. Moore (Principia Ethica [1903], §112) | |
| A reaction: This is known as the 'isolation test'. The test has an instant appeal, but looks a bit odd after a little thought. The value of most things drains out of them if they are totally isolated. The MS of the Goldberg Variations floating in outer space? |
| 11057 | It is always an open question whether anything that is natural is good [Moore,GE] |
| Full Idea: Good does not, by definition, mean anything that is natural; and it is therefore always an open question whether anything that is natural is good. | |
| From: G.E. Moore (Principia Ethica [1903], §027) | |
| A reaction: This is the best known modern argument for Platonist idealised ethics. But maybe there is no end to questioning anywhere, so each theory invites a further question, and nothing is ever fully explained? Next stop - pragmatism. |
| 5925 | The three main values are good, right and beauty [Moore,GE, by Ross] |
| Full Idea: Moore describes rightness and beauty as the two main value-attributes, apart from goodness. | |
| From: report of G.E. Moore (Principia Ethica [1903]) by W. David Ross - The Right and the Good §IV | |
| A reaction: This was a last-throw of the Platonic ideal, before we plunged into the value-free world of Darwin and the physicists. It is hard to agree with Moore, but also hard to disagree. Why do many people despise or ignore these values? |
| 5902 | For Moore, 'right' is what produces good [Moore,GE, by Ross] |
| Full Idea: Moore claims that 'right' means 'productive of the greatest possible good'. | |
| From: report of G.E. Moore (Principia Ethica [1903]) by W. David Ross - The Right and the Good §I | |
| A reaction: Ross is at pains to keep 'right' and 'good' as quite distinct notions. Some actions are right but very unpleasant, and seem to produce no real good at all. |
| 5903 | 'Right' means 'cause of good result' (hence 'useful'), so the end does justify the means [Moore,GE] |
| Full Idea: 'Right' does and can mean nothing but 'cause of a good result', and is thus identical with 'useful', whence it follows that the end always will justify the means. | |
| From: G.E. Moore (Principia Ethica [1903], §089) | |
| A reaction: Of course, Moore does not identify utility with pleasure, as his notion of what is good concerns fairly Platonic ideals. Would Stalin's murders have been right if Russia were now the happiest nation on Earth? |
| 5907 | Relationships imply duties to people, not merely the obligation to benefit them [Ross on Moore,GE] |
| Full Idea: Moore's 'Ideal Utilitarianism' seems to unduly simplify our relations to our fellows. My neighbours are merely possible beneficiaries by my action. But they also stand to me as promiser, creditor, husband, friend, which entails prima facie duties. | |
| From: comment on G.E. Moore (Principia Ethica [1903]) by W. David Ross - The Right and the Good §II | |
| A reaction: Perhaps it is better to say that we have obligations to benefit particular people, because of our obligations, and that we are confined to particular benefits which meet those obligations - not just any old benefit to any old person. |
| 7829 | God no more has human perfections than we have animal perfections [Spinoza] |
| Full Idea: To ascribe to God those attributes which make a man perfect would be as wrong as to ascribe to a man the attributes that make perfect an elephant or an ass. | |
| From: Baruch de Spinoza (Letters to Blijenburgh [1665], 1665), quoted by Matthew Stewart - The Courtier and the Heretic Ch.10 | |
| A reaction: This would be a difficulty for Aquinas's Fourth Way (Idea 1432), and one which I think Aquinas might acknowledge, given his desire that we should be humble when trying to comprehend God (Idea 1410). It leaves us struggling to grasp the concept of God. |
| 7830 | A talking triangle would say God is triangular [Spinoza] |
| Full Idea: If a triangle could speak it would say that God is eminently triangular. | |
| From: Baruch de Spinoza (Letters to Blijenburgh [1665], 1665), quoted by Matthew Stewart - The Courtier and the Heretic Ch.10 | |
| A reaction: Spinoza had a rather appealing waspish wit. This nicely dramatises an ancient idea (Idea 407). You can, of course, if you believe in God, infer some of His characteristics from His creation. But then see Hume: Ideas 1439, 6960, 6967, 1440. |