28 ideas
16123 | Whenever you perceive a community of things, you should also hunt out differences in the group [Plato] |
Full Idea: The rule is that when one perceives first the community between the members of a group of many things, one should not desist until one sees in it all those differences that are located in classes. | |
From: Plato (The Statesman [c.356 BCE], 285b) | |
A reaction: He goes on to recommend the opposite as well - see community even when there appears to be nothing but differences. I take this to be analysis, just as much as modern linguistic approaches are. Analyse the world, not language. |
16125 | To reveal a nature, divide down, and strip away what it has in common with other things [Plato] |
Full Idea: Let's take the kind posited and cut it in two, .then follow the righthand part of what we've cut, and hold onto things that the sophist is associated with until we strip away everything he has in common with other things, then display his peculiar nature. | |
From: Plato (The Statesman [c.356 BCE], 264e) | |
A reaction: This seems to be close to Aristotle's account of definition, when he is trying to get at what-it-is-to-be some thing. But if you strip away everything the definiendum has in common with other things, will anything remain? |
16124 | No one wants to define 'weaving' just for the sake of weaving [Plato] |
Full Idea: I don't suppose that anyone with any sense would want to hunt down the definition of 'weaving' for the sake of weaving itself. | |
From: Plato (The Statesman [c.356 BCE], 285d) | |
A reaction: The point seems to be that the definition brings out the connections between weaving and other activities and objects, thus enlarging our understanding. |
12452 | Our dislike of contradiction in logic is a matter of psychology, not mathematics [Brouwer] |
Full Idea: Not to the mathematician, but to the psychologist, belongs the task of explaining why ...we are averse to so-called contradictory systems in which the negative as well as the positive of certain propositions are valid. | |
From: Luitzen E.J. Brouwer (Intuitionism and Formalism [1912], p.79) | |
A reaction: Was the turning point of Graham Priest's life the day he read this sentence? I don't agree. I take the principle of non-contradiction to be a highly generalised observation of how the world works (and Russell agrees with me). |
11115 | 'All horses' either picks out the horses, or the things which are horses [Jubien] |
Full Idea: Two ways to see 'all horses are animals' are as picking out all the horses (so that it is a 'horse-quantifier'), ..or as ranging over lots of things in addition to horses, with 'horses' then restricting the things to those that satisfy 'is a horse'. | |
From: Michael Jubien (Analyzing Modality [2007], 2) | |
A reaction: Jubien says this gives you two different metaphysical views, of a world of horses etc., or a world of things which 'are horses'. I vote for the first one, as the second seems to invoke an implausible categorical property ('being a horse'). Cf Idea 11116. |
12451 | Scientific laws largely rest on the results of counting and measuring [Brouwer] |
Full Idea: A large part of the natural laws introduced by science treat only of the mutual relations between the results of counting and measuring. | |
From: Luitzen E.J. Brouwer (Intuitionism and Formalism [1912], p.77) | |
A reaction: His point, I take it, is that the higher reaches of numbers have lost touch with the original point of the system. I now see the whole issue as just depending on conventions about the agreed extension of the word 'number'. |
12454 | Intuitionists only accept denumerable sets [Brouwer] |
Full Idea: The intuitionist recognises only the existence of denumerable sets. | |
From: Luitzen E.J. Brouwer (Intuitionism and Formalism [1912], p.80) | |
A reaction: That takes you up to omega, but not beyond, presumably because it then loses sight of the original intuition of 'bare two-oneness' (Idea 12453). I sympathise, but the word 'number' has shifted its meaning a lot these days. |
12453 | Neo-intuitionism abstracts from the reuniting of moments, to intuit bare two-oneness [Brouwer] |
Full Idea: Neo-intuitionism sees the falling apart of moments, reunited while remaining separated in time, as the fundamental phenomenon of human intellect, passing by abstracting to mathematical thinking, the intuition of bare two-oneness. | |
From: Luitzen E.J. Brouwer (Intuitionism and Formalism [1912], p.80) | |
A reaction: [compressed] A famous and somewhat obscure idea. He goes on to say that this creates one and two, and all the finite ordinals. |
11116 | Being a physical object is our most fundamental category [Jubien] |
Full Idea: Being a physical object (as opposed to being a horse or a statue) really is our most fundamental category for dealing with the external world. | |
From: Michael Jubien (Analyzing Modality [2007], 2) | |
A reaction: This raises the interesting question of why any categories should be considered to be more 'fundamental' than others. I can only think that we perceive something to be an object fractionally before we (usually) manage to identify it. |
11117 | Haecceities implausibly have no qualities [Jubien] |
Full Idea: Properties of 'being such and such specific entity' are often called 'haecceities', but this term carries the connotation of non-qualitativeness which I don't favour. | |
From: Michael Jubien (Analyzing Modality [2007], 2) | |
A reaction: The way he defines it makes it sound as if it was a category, but I take it to be more like a bare individual essence. If it has not qualities then it has no causal powers, so there could be no evidence for its existence. |
11119 | De re necessity is just de dicto necessity about object-essences [Jubien] |
Full Idea: I suggest that the de re is to be analyzed in terms of the de dicto. ...We have a case of modality de re when (and only when) the appropriate property in the de dicto formulation is an object-essence. | |
From: Michael Jubien (Analyzing Modality [2007], 5) |
11118 | Modal propositions transcend the concrete, but not the actual [Jubien] |
Full Idea: Where modal propositions may once have seemed to transcend the actual, they now seem only to transcend the concrete. | |
From: Michael Jubien (Analyzing Modality [2007], 4) | |
A reaction: This is because Jubien has defended a form of platonism. Personally I take modal propositions to be perceptible in the concrete world, by recognising the processes involved, not the mere static stuff. |
11108 | Your properties, not some other world, decide your possibilities [Jubien] |
Full Idea: The possibility of your having been a playwright has nothing to do with how people are on other planets, whether in our own or in some other realm. It is only to do with you and the relevant property. | |
From: Michael Jubien (Analyzing Modality [2007], 1) | |
A reaction: I'm inclined to think that this simple point is conclusive disproof of possible worlds as an explanation of modality (apart from Jubien's other nice points). What we need to understand are modal properties, not other worlds. |
11111 | Modal truths are facts about parts of this world, not about remote maximal entities [Jubien] |
Full Idea: Typical modal truths are just facts about our world, and generally facts about very small parts of it, not facts about some infinitude of complex, maximal entities. | |
From: Michael Jubien (Analyzing Modality [2007], 1) | |
A reaction: I think we should embrace this simple fact immediately, and drop all this nonsense about possible worlds, even if they are useful for the semantics of modal logic. |
11105 | We have no idea how many 'possible worlds' there might be [Jubien] |
Full Idea: As soon as we start talking about 'possible world', we beg the question of their relevance to our prior notion of possibility. For all we know, there are just two such realms, or twenty-seven, or uncountably many, or even set-many. | |
From: Michael Jubien (Analyzing Modality [2007], 1) |
11107 | If there are no other possible worlds, do we then exist necessarily? [Jubien] |
Full Idea: Suppose there happen to be no other concrete realms. Would we happily accept the consequence that we exist necessarily? | |
From: Michael Jubien (Analyzing Modality [2007], 1) |
11106 | If all possible worlds just happened to include stars, their existence would be necessary [Jubien] |
Full Idea: If all of the possible worlds happened to include stars, how plausible is it to think that if this is how things really are, then we've just been wrong to regard the existence of stars as contingent? | |
From: Michael Jubien (Analyzing Modality [2007], 1) |
11112 | Possible worlds just give parallel contingencies, with no explanation at all of necessity [Jubien] |
Full Idea: In the world theory, what passes for 'necessity' is just a bunch of parallel 'contingencies'. The theory provides no basis for understanding why these contingencies repeat unremittingly across the board (while others do not). | |
From: Michael Jubien (Analyzing Modality [2007], 1) |
11109 | If other worlds exist, then they are scattered parts of the actual world [Jubien] |
Full Idea: Any other realms that happened to exist would just be scattered parts of the actual world, not entire worlds at all. It would just happen that physical reality was fragmented in this remarkable but modally inconsequential way. | |
From: Michael Jubien (Analyzing Modality [2007], 1) | |
A reaction: This is aimed explicitly at Lewis's modal realism, and strikes me as correct. Jubien's key point here is that they are irrelevant to modality, just as foreign countries are irrelevant to the modality of this one. |
11113 | Worlds don't explain necessity; we use necessity to decide on possible worlds [Jubien] |
Full Idea: The suspicion is that the necessity doesn't arise from how worlds are, but rather that the worlds are taken to be as they are in order to capture the intuitive necessity. | |
From: Michael Jubien (Analyzing Modality [2007], 1) | |
A reaction: It has always seemed to me rather glaring that you need a prior notion of 'possible' before you can start to talk about 'possible worlds', but I have always been too timid to disagree with the combination of Saul Kripke and David Lewis. Thank you, Jubien! |
11110 | We mustn't confuse a similar person with the same person [Jubien] |
Full Idea: If someone similar to Humphrey won the election, that nicely establishes the possibility of someone's winning who is similar to Humphrey. But we mustn't confuse this possibility with the intuitively different possibility of Humphrey himself winning. | |
From: Michael Jubien (Analyzing Modality [2007], 1) |
5961 | The soul gets its goodness from god, and its evil from previous existence. [Plato] |
Full Idea: From its composer the soul possesses all beautiful things, but from its former condition, everything that proves to be harsh and unjust in heaven. | |
From: Plato (The Statesman [c.356 BCE], 273b) | |
A reaction: A neat move to explain the origins of evil (or rather, to shift the problem of evil to a long long way from here). This view presumably traces back to the views of Empedocles on good and evil. Can the soul acquire evil in its current existence? |
10117 | Intuitonists in mathematics worried about unjustified assertion, as well as contradiction [Brouwer, by George/Velleman] |
Full Idea: The concern of mathematical intuitionists was that the use of certain forms of inference generates, not contradiction, but unjustified assertions. | |
From: report of Luitzen E.J. Brouwer (Intuitionism and Formalism [1912]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.6 | |
A reaction: This seems to be the real origin of the verificationist idea in the theory of meaning. It is a hugely revolutionary idea - that ideas are not only ruled out of court by contradiction, but that there are other criteria which should also be met. |
283 | The question of whether or not to persuade comes before the science of persuasion [Plato] |
Full Idea: The science of whether one must persuade or not must rule over the science capable of persuading. | |
From: Plato (The Statesman [c.356 BCE], 304c) | |
A reaction: Plato probably thinks that reason has to be top of the pyramid, but there is always the Nietzschean/romantic question of why we should place such a value on what is rational. |
282 | Non-physical beauty can only be shown clearly by speech [Plato] |
Full Idea: The bodiless things, being the most beautiful and the greatest, are only shown with clarity by speech and nothing else. | |
From: Plato (The Statesman [c.356 BCE], 286a) | |
A reaction: Unfortunately this will be true of warped and ugly ideas as well. |
281 | The arts produce good and beautiful things by preserving the mean [Plato] |
Full Idea: It is by preserving the mean that arts produce everything that is good and beautiful. | |
From: Plato (The Statesman [c.356 BCE], 284b) |
22559 | Democracy is the worst of good constitutions, but the best of bad constitutions [Plato, by Aristotle] |
Full Idea: Plato judged that when the constitution is decent, democracy is the worst of them, but when they are bad it is the best. | |
From: report of Plato (The Statesman [c.356 BCE], 302e) by Aristotle - Politics 1289b07 | |
A reaction: Aristotle denies that a good oligarchy is superior. What of technocracy? The challenge is to set up institutions which ensure the health of the democracy. The big modern problem is populists who lie. |
279 | Only divine things can always stay the same, and bodies are not like that [Plato] |
Full Idea: It is fitting for only the most divine things of all to be always the same and in the same state and in the same respects, and the nature of body is not of this ordering. | |
From: Plato (The Statesman [c.356 BCE], 269b) |