30 ideas
21750 | Science is sympathetic to truth as correspondence, since it depends on observation [Quine] |
Full Idea: Science, thanks to its links with observation, retains some title to a correspondence theory of truth. | |
From: Willard Quine (On the Nature of Moral Values [1978], p.63) | |
A reaction: I would describe what he is affirming as a 'robust' theory of truth. An interesting aside, given his usual allegiance to disquotational, and even redundancy, accounts of truth. You can hardly rely on observations if you think they contain no truth. |
10807 | Mathematics reduces to set theory, which reduces, with some mereology, to the singleton function [Lewis] |
Full Idea: It is generally accepted that mathematics reduces to set theory, and I argue that set theory in turn reduces, with some aid of mereology, to the theory of the singleton function. | |
From: David Lewis (Mathematics is Megethology [1993], p.03) |
10809 | We can accept the null set, but not a null class, a class lacking members [Lewis] |
Full Idea: In my usage of 'class', there is no such things as the null class. I don't mind calling some memberless thing - some individual - the null set. But that doesn't make it a memberless class. Rather, that makes it a 'set' that is not a class. | |
From: David Lewis (Mathematics is Megethology [1993], p.05) | |
A reaction: Lewis calls this usage 'idiosyncratic', but it strikes me as excellent. Set theorists can have their vital null class, and sensible people can be left to say, with Lewis, that classes of things must have members. |
10811 | The null set plays the role of last resort, for class abstracts and for existence [Lewis] |
Full Idea: The null set serves two useful purposes. It is a denotation of last resort for class abstracts that denote no nonempty class. And it is an individual of last resort: we can count on its existence, and fearlessly build the hierarchy of sets from it. | |
From: David Lewis (Mathematics is Megethology [1993], p.09) | |
A reaction: This passage assuages my major reservation about the existence of the null set, but at the expense of confirming that it must be taken as an entirely fictional entity. |
10812 | The null set is not a little speck of sheer nothingness, a black hole in Reality [Lewis] |
Full Idea: Should we accept the null set as a most extraordinary individual, a little speck of sheer nothingness, a sort of black hole in the fabric of Reality itself? Not that either, I think. | |
From: David Lewis (Mathematics is Megethology [1993], p.09) | |
A reaction: Correct! |
10813 | What on earth is the relationship between a singleton and an element? [Lewis] |
Full Idea: A new student of set theory has just one thing, the element, and he has another single thing, the singleton, and not the slightest guidance about what one thing has to do with the other. | |
From: David Lewis (Mathematics is Megethology [1993], p.12) |
10814 | Are all singletons exact intrinsic duplicates? [Lewis] |
Full Idea: Are all singletons exact intrinsic duplicates? | |
From: David Lewis (Mathematics is Megethology [1993], p.13) |
10806 | Megethology is the result of adding plural quantification to mereology [Lewis] |
Full Idea: Megethology is the result of adding plural quantification, as advocated by George Boolos, to the language of mereology. | |
From: David Lewis (Mathematics is Megethology [1993], p.03) |
10816 | We can use mereology to simulate quantification over relations [Lewis] |
Full Idea: We can simulate quantification over relations using megethology. Roughly, a quantifier over relations is a plural quantifier over things that encode ordered pairs by mereological means. | |
From: David Lewis (Mathematics is Megethology [1993], p.18) | |
A reaction: [He credits this idea to Burgess and Haven] The point is to avoid second-order logic, which quantifies over relations as ordered n-tuple sets. |
10808 | Mathematics is generalisations about singleton functions [Lewis] |
Full Idea: We can take the theory of singleton functions, and hence set theory, and hence mathematics, to consist of generalisations about all singleton functions. | |
From: David Lewis (Mathematics is Megethology [1993], p.03) | |
A reaction: At first glance this sounds like a fancy version of the somewhat discredited Greek idea that mathematics is built on the concept of a 'unit'. |
10815 | We don't need 'abstract structures' to have structural truths about successor functions [Lewis] |
Full Idea: We needn't believe in 'abstract structures' to have general structural truths about all successor functions. | |
From: David Lewis (Mathematics is Megethology [1993], p.16) |
9476 | If dispositions are more fundamental than causes, then they won't conceptually reduce to them [Bird on Lewis] |
Full Idea: Maybe a disposition is a more fundamental notion than a cause, in which case Lewis has from the very start erred in seeking a causal analysis, in a traditional, conceptual sense, of disposition terms. | |
From: comment on David Lewis (Causation [1973]) by Alexander Bird - Nature's Metaphysics 2.2.8 | |
A reaction: Is this right about Lewis? I see him as reducing both dispositions and causes to a set of bald facts, which exist in possible and actual worlds. Conditionals and counterfactuals also suffer the same fate. |
10810 | I say that absolutely any things can have a mereological fusion [Lewis] |
Full Idea: I accept the principle of Unrestricted Composition: whenever there are some things, no matter how many or how unrelated or how disparate in character they may be, they have a mereological fusion. ...The trout-turkey is part fish and part fowl. | |
From: David Lewis (Mathematics is Megethology [1993], p.07) | |
A reaction: This nicely ducks the question of when things form natural wholes and when they don't, but I would have thought that that might be one of the central issues of metaphysicals, so I think I'll give Lewis's principle a miss. |
8425 | For true counterfactuals, both antecedent and consequent true is closest to actuality [Lewis] |
Full Idea: A counterfactual is non-vacuously true iff it takes less of a departure from actuality to make the consequent true along with the antecedent than it does to make the antecedent true without the consequent. | |
From: David Lewis (Causation [1973], p.197) | |
A reaction: Almost every theory proposed by Lewis hangs on the meaning of the word 'close', as used here. If you visited twenty Earth-like worlds (watch Startrek?), it would be a struggle to decide their closeness to ours in rank order. |
21748 | More careful inductions gradually lead to the hypothetico-deductive method [Quine] |
Full Idea: Our inductions become increasingly explicit and deliberate, and in the fulness of time we even rise above induction, to the hypothetico-deductive method. | |
From: Willard Quine (On the Nature of Moral Values [1978], p.57) | |
A reaction: This seems to defer to Hempel's account of scientific theorising. I wander what exactly 'rising above' means? |
8424 | Determinism says there can't be two identical worlds up to a time, with identical laws, which then differ [Lewis] |
Full Idea: By determinism I mean that the prevailing laws of nature are such that there do not exist any two possible worlds which are exactly alike up to that time, which differ thereafter, and in which those laws are never violated. | |
From: David Lewis (Causation [1973], p.196) | |
A reaction: This would mean that the only way an action of free will could creep in would be if it accepted being a 'violation' of the laws of nature. Fans of free will would probably prefer to call it a 'natural' phenomenon. I'm with Lewis. |
8420 | A proposition is a set of possible worlds where it is true [Lewis] |
Full Idea: I identify a proposition with the set of possible worlds where it is true. | |
From: David Lewis (Causation [1973], p.193) | |
A reaction: As it stands, I'm baffled by this. How can 'it is raining' be a set of possible worlds? I assume it expands to refer to the truth-conditions, among possibilities as well as actualities. 'It is raining' fits all worlds where it is raining. |
21749 | Altruistic values concern other persons, and ceremonial values concern practices [Quine] |
Full Idea: Altruistic values attach to satisfactions of other persons, without regard to ulterior satisfactions accruing to oneself. Ceremonial values attach to practices of one's society, without regard to satisfactions accruing to oneself. | |
From: Willard Quine (On the Nature of Moral Values [1978], p.58) | |
A reaction: An interesting distinction, but probably as blurred and circular as (according to Quine) the analytic/synthetic distinction. |
21751 | Love seems to diminish with distance from oneself [Quine] |
Full Idea: One cannot reasonably be called upon to love even one's neighbour quite as oneself. Is love to diminish inversely as the square of the distance? Is it to extend to other species than one's own? | |
From: Willard Quine (On the Nature of Moral Values [1978], p.65) | |
A reaction: Quine isn't actually saying that love is inherently egoistic, but that is the implication. The power of my love is at its most powerful when it is closest to home. |
8405 | A theory of causation should explain why cause precedes effect, not take it for granted [Lewis, by Field,H] |
Full Idea: Lewis thinks it is a major defect in a theory of causation that it builds in the condition that the time of the cause precede that of the effect: that cause precedes effect is something we ought to explain (which his counterfactual theory claims to do). | |
From: report of David Lewis (Causation [1973]) by Hartry Field - Causation in a Physical World | |
A reaction: My immediate reaction is that the chances of explaining such a thing are probably nil, and that we might as well just accept the direction of causation as a given. Even philosophers balk at the question 'why doesn't time go backwards?' |
8427 | I reject making the direction of causation axiomatic, since that takes too much for granted [Lewis] |
Full Idea: One might stipulate that a cause must always precede its effect, but I reject this solution. It won't solve the problem of epiphenomena, it rejects a priori any backwards causation, and it trivializes defining time-direction through causation. | |
From: David Lewis (Causation [1973], p.203) | |
A reaction: [compressed] Not strong arguments, I would say. Maybe apparent causes are never epiphenomenal. Maybe backwards causation is impossible. Maybe we must use time to define causal direction, and not vice versa. |
10392 | It is just individious discrimination to pick out one cause and label it as 'the' cause [Lewis] |
Full Idea: We sometimes single out one among all the causes of some event and call it 'the' cause. ..We may select the abnormal causes, or those under human control, or those we deem good or bad, or those we want to talk about. This is invidious discrimination. | |
From: David Lewis (Causation [1973]) | |
A reaction: This is the standard view expressed by Mill - presumably the obvious empiricist line. But if we specify 'the pre-conditions' for an event, we can't just mention ANY fact prior to the effect - there is obvious relevance. So why not for 'the' cause as well? |
8419 | The modern regularity view says a cause is a member of a minimal set of sufficient conditions [Lewis] |
Full Idea: In present-day regularity analyses, a cause is defined (roughly) as any member of any minimal set of actual conditions that are jointly sufficient, given the laws, for the existence of the effect. | |
From: David Lewis (Causation [1973], p.193) | |
A reaction: This is the view Lewis is about to reject. It seem to summarise the essence of the Mackie INUS theory. This account would make the presence of oxygen a cause of almost every human event. |
8421 | Regularity analyses could make c an effect of e, or an epiphenomenon, or inefficacious, or pre-empted [Lewis] |
Full Idea: In the regularity analysis of causes, instead of c causing e, c might turn out to be an effect of e, or an epiphenomenon, or an inefficacious effect of a genuine cause, or a pre-empted cause (by some other cause) of e. | |
From: David Lewis (Causation [1973], p.194) | |
A reaction: These are Lewis's reasons for rejecting the general regularity account, in favour of his own particular counterfactual account. It is unlikely that c would be regularly pre-empted or epiphenomenal. If we build time's direction in, it won't be an effect. |
17525 | The counterfactual view says causes are necessary (rather than sufficient) for their effects [Lewis, by Bird] |
Full Idea: The Humean idea, developed by Lewis, is that rather than being sufficient for their effects, causes are (counterfactual) necessary for their effects. | |
From: report of David Lewis (Causation [1973]) by Alexander Bird - Causation and the Manifestation of Powers p.162 |
17524 | Lewis has basic causation, counterfactuals, and a general ancestral (thus handling pre-emption) [Lewis, by Bird] |
Full Idea: Lewis's basic account has a basic causal relation, counterfactual dependence, and the general causal relation is the ancestral of this basic one. ...This is motivated by counterfactual dependence failing to be general because of the pre-emption problem. | |
From: report of David Lewis (Causation [1973]) by Alexander Bird - Causation and the Manifestation of Powers p.161 | |
A reaction: It is so nice when you struggle for ages with a topic, and then some clever person summarises it clearly for you. |
8397 | Counterfactual causation implies all laws are causal, which they aren't [Tooley on Lewis] |
Full Idea: Some counterfactuals are based on non-causal laws, such as Newton's Third Law of Motion. 'If no force one way, then no force the other'. Lewis's counterfactual analysis implies that one force causes the other, which is not the case. | |
From: comment on David Lewis (Causation [1973]) by Michael Tooley - Causation and Supervenience 5.2 | |
A reaction: So what exactly does 'cause' my punt to move forwards? Basing causal laws on counterfactual claims looks to me like putting the cart before the horse. |
8423 | My counterfactual analysis applies to particular cases, not generalisations [Lewis] |
Full Idea: My (counterfactual) analysis is meant to apply to causation in particular cases; it is not an analysis of causal generalizations. Those presumably quantify over particulars, but it is hard to match natural language to the quantifiers. | |
From: David Lewis (Causation [1973], p.195) | |
A reaction: What authority could you have for asserting a counterfactual claim, if you only had one observation? Isn't the counterfactual claim the hallmark of a generalisation? For one case, 'if not-c, then not-e' is just a speculation. |
8426 | One event causes another iff there is a causal chain from first to second [Lewis] |
Full Idea: One event is the cause of another iff there exists a causal chain leading from the first to the second. | |
From: David Lewis (Causation [1973], p.200) | |
A reaction: It will be necessary to both explain and identify a 'chain'. Some chains are extremely tenuous (Alexander could stop a barrel of beer). Go back a hundred years, and the cause of any present event is everything back then. |
4795 | Lewis's account of counterfactuals is fine if we know what a law of nature is, but it won't explain the latter [Cohen,LJ on Lewis] |
Full Idea: Lewis can elucidate the logic of counterfactuals on the assumption that you are not at all puzzled about what a law of nature is. But if you are puzzled about this, it cannot contribute anything towards resolving your puzzlement. | |
From: comment on David Lewis (Causation [1973]) by L. Jonathan Cohen - The Problem of Natural Laws p.219 | |
A reaction: This seems like a penetrating remark. The counterfactual theory is wrong, partly because it is epistemological instead of ontological, and partly because it refuses to face the really difficult problem, of what is going on out there. |