11 ideas
| 4037 | Ockham's Razor is the principle that we need reasons to believe in entities [Mellor/Oliver] |
| Full Idea: Ockham's Razor is the principle that we need reasons to believe in entities. | |
| From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §9) | |
| A reaction: This presumably follows from an assumption that all beliefs need reasons, but is that the case? The Principle of Sufficient Reason precedes Ockham's Razor. |
| 9944 | We understand some statements about all sets [Putnam] |
| Full Idea: We seem to understand some statements about all sets (e.g. 'for every set x and every set y, there is a set z which is the union of x and y'). | |
| From: Hilary Putnam (Mathematics without Foundations [1967], p.308) | |
| A reaction: His example is the Axiom of Choice. Presumably this is why the collection of all sets must be referred to as a 'class', since we can talk about it, but cannot define it. |
| 9937 | I do not believe mathematics either has or needs 'foundations' [Putnam] |
| Full Idea: I do not believe mathematics either has or needs 'foundations'. | |
| From: Hilary Putnam (Mathematics without Foundations [1967]) | |
| A reaction: Agreed that mathematics can function well without foundations (given that the enterprise got started with no thought for such things), the ontology of the subject still strikes me as a major question, though maybe not for mathematicians. |
| 9939 | It is conceivable that the axioms of arithmetic or propositional logic might be changed [Putnam] |
| Full Idea: I believe that under certain circumstances revisions in the axioms of arithmetic, or even of the propositional calculus (e.g. the adoption of a modular logic as a way out of the difficulties in quantum mechanics), is fully conceivable. | |
| From: Hilary Putnam (Mathematics without Foundations [1967], p.303) | |
| A reaction: One can change the axioms of a system without necessarily changing the system (by swapping an axiom and a theorem). Especially if platonism is true, since the eternal objects reside calmly above our attempts to axiomatise them! |
| 9940 | Maybe mathematics is empirical in that we could try to change it [Putnam] |
| Full Idea: Mathematics might be 'empirical' in the sense that one is allowed to try to put alternatives into the field. | |
| From: Hilary Putnam (Mathematics without Foundations [1967], p.303) | |
| A reaction: He admits that change is highly unlikely. It take hardcore Millian arithmetic to be only changeable if pebbles start behaving very differently with regard to their quantities, which appears to be almost inconceivable. |
| 9941 | Science requires more than consistency of mathematics [Putnam] |
| Full Idea: Science demands much more of a mathematical theory than that it should merely be consistent, as the example of the various alternative systems of geometry dramatizes. | |
| From: Hilary Putnam (Mathematics without Foundations [1967]) | |
| A reaction: Well said. I don't agree with Putnam's Indispensability claims, but if an apparent system of numbers or lines has no application to the world then I don't consider it to be mathematics. It is a new game, like chess. |
| 9943 | You can't deny a hypothesis a truth-value simply because we may never know it! [Putnam] |
| Full Idea: Surely the mere fact that we may never know whether the continuum hypothesis is true or false is by itself just no reason to think that it doesn't have a truth value! | |
| From: Hilary Putnam (Mathematics without Foundations [1967]) | |
| A reaction: This is Putnam in 1967. Things changed later. Personally I am with the younger man all they way, but I reserve the right to totally change my mind. |
| 4027 | Properties are respects in which particular objects may be alike or differ [Mellor/Oliver] |
| Full Idea: Properties are respects in which particular objects may be alike or differ. | |
| From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §1) | |
| A reaction: Note that this definition does not mention a causal role for properties. |
| 4029 | Nominalists ask why we should postulate properties at all [Mellor/Oliver] |
| Full Idea: Nominalists ask why we should postulate properties at all. | |
| From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §3) | |
| A reaction: Objects might be grasped without language, but events cannot be understood, and explanations of events seem inconceivable without properties (implying that they are essentially causal). |
| 4039 | Abstractions lack causes, effects and spatio-temporal locations [Mellor/Oliver] |
| Full Idea: Abstract entities (such as sets) are usually understood as lacking causes, effects, and spatio-temporal location. | |
| From: DH Mellor / A Oliver (Introduction to 'Properties' [1997], §10) | |
| A reaction: This seems to beg some questions. Has the ideal of 'honour' never caused anything? Young men dream of pure velocity. |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| Full Idea: In singing and playing the lyre, a boy will be likely to reveal not only courage and moderation, but also justice. | |
| From: Damon (fragments/reports [c.460 BCE], B4), quoted by (who?) - where? |