15 ideas
| 13407 | All worthwhile philosophy is synthetic theorizing, evaluated by experience [Papineau] |
| Full Idea: I would say that all worthwhile philosophy consists of synthetic theorizing, evaluated against experience. | |
| From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §1) | |
| A reaction: This is the view that philosophy is just science at a high level of abstraction, and he explicitly rejects 'conceptual analysis' as a fruitful activity. I need to take a stance on this one, but find I am in a state of paralysis. Welcome to philosophy... |
| 16951 | It was realised that possible worlds covered all modal logics, if they had a structure [Dummett] |
| Full Idea: The new discovery was that with a suitable structure imposed on the space of possible worlds, the Leibnizian idea would work for all modal logics. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 1) |
| 16952 | If something is only possible relative to another possibility, the possibility relation is not transitive [Dummett] |
| Full Idea: If T is only possible if S obtains, and S is possible but doesn't obtain, then T is only possible in the world where S obtains, but T is not possible in the actual world. It follows that the relation of relative possibility is not transitive. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 1) | |
| A reaction: [compressed] |
| 16953 | Relative possibility one way may be impossible coming back, so it isn't symmetrical [Dummett] |
| Full Idea: If T is only possible if S obtains, T and S hold in the actual world, and S does not obtain in world v possible relative to the actual world, then the actual is not possible relative to v, since T holds in the actual. Accessibility can't be symmetrical. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 1) |
| 16960 | If possibilitiy is relative, that might make accessibility non-transitive, and T the correct system [Dummett] |
| Full Idea: If some world is 'a way the world might be considered to be if things were different in a certain respect', that might show that the accessibility relation should not be taken to be transitive, and we should have to adopt modal logic T. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 8) | |
| A reaction: He has already rejected symmetry from the relation, for reasons concerning relative identity. He is torn between T and S4, but rejects S5, and opts not to discuss it. |
| 16958 | In S4 the actual world has a special place [Dummett] |
| Full Idea: In S4 logic the actual world is, in itself, special, not just from our point of view. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 8) | |
| A reaction: S4 lacks symmetricality, so 'you can get there, but you can't get back', which makes the starting point special. So if you think the actual world has a special place in modal metaphysics, you must reject S5? |
| 13409 | Our best theories may commit us to mathematical abstracta, but that doesn't justify the commitment [Papineau] |
| Full Idea: Our empirically best-supported theories may commit us to certain abstract mathematical entities, but this does not necessarily mean that this is what justifies our commitment. That we are committed doesn't explain why we should be. | |
| From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §4) | |
| A reaction: A nice point. It is only a slightly gormless scientism which would say that we have to accept whatever scientists demand. Who's in charge here - scientists, mathematicians or philosophers? Don't answer that... |
| 16957 | Possible worlds aren't how the world might be, but how a world might be, given some possibility [Dummett] |
| Full Idea: The equation of a possible world with the way that the (actual) world might be is wrong: the way a distant world might be is not a way the world might be, but a way we might allow it to be given how some intervening world might be. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 8) | |
| A reaction: The point here is that a system of possible worlds must include relative possibilities as well as actual possibilities. Dummett argues against S5 modal logic, which makes them all equal. Things impossible here might become possible. Nice. |
| 16959 | If possible worlds have no structure (S5) they are equal, and it is hard to deny them reality [Dummett] |
| Full Idea: If our space of possible worlds has no structure, as in the semantics for S5, then, from the standpoint of the semantics, all possible worlds are on the same footing; it then becomes difficult to resist the claim that all are equally real. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 8) | |
| A reaction: This is a rather startling and interesting claim, given that modern philosophy seems full of thinkers who both espouse S5 for metaphysics, and also deny Lewisian realism about possible worlds. I'll ponder that one. Must read the new Williamson…. |
| 13406 | A priori knowledge is analytic - the structure of our concepts - and hence unimportant [Papineau] |
| Full Idea: I am a fully paid up-naturalist, but I see no reason to deny that a priori knowledge is possible. My view is that a priori knowledge is unimportant (esp to philosophy). If there is a priori knowledge, it is analytic, true by the structure of our concepts. | |
| From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §1) | |
| A reaction: It is one thing to say it is the structure of our concepts, and another to infer that it is unimportant. I take the structure of our concepts to be a shadow cast by the structure of the world. E.g. the structure of numbers reveals the world. |
| 13408 | Intuition and thought-experiments embody substantial information about the world [Papineau] |
| Full Idea: Naturalists can allow for thought-experiments in philosophy. Intuitions play an important role, but only because they embody substantial information about the world. | |
| From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §3) | |
| A reaction: In this sense, intuitions are just memories which are too complex for us to articulate. They are not the intuitions of 'pure reason'. It is hard to connect the intuitive spotting of a proof with memories of the physical world. |
| 13410 | Verificationism about concepts means you can't deny a theory, because you can't have the concept [Papineau] |
| Full Idea: Verificationism about concepts implies that thinkers will not share concepts with adherents of theories they reject. Those who reject the phlogiston theory will not possess the same concept as adherents, so cannot say 'there is no phlogiston'. | |
| From: David Papineau (Philosophical Insignificance of A Priori Knowledge [2010], §6) | |
| A reaction: The point seems to be more general - that it is hard to see how you can have a concept of anything which doesn't actually exist, if the concept is meant to rest on some sort of empirical verification. |
| 16956 | To explain generosity in a person, you must understand a generous action [Dummett] |
| Full Idea: It cannot be explained what it is for a person to be generous without first explaining what it is for an action to be generous. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 4) | |
| A reaction: I presume a slot machine can't be 'generous', even if it favours the punter, so you can't specify a generous action without making reference to the person. A benign circle, as Aristotle says. |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
| From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
| A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |
| 16954 | Generalised talk of 'natural kinds' is unfortunate, as they vary too much [Dummett] |
| Full Idea: In my view, Kripke's promotion of 'natural kinds', coverning chemical substances and animal and plant species, is unfortunate, since these are rather different types of things, and words used for them behave differently. | |
| From: Michael Dummett (Could There Be Unicorns? [1983], 2) | |
| A reaction: My view is that the only significant difference among natural kinds is their degree of stability in character. Presumably particles, elements and particular molecules are fairly invariant, but living things evolve. |