45 ideas
14684 | A world is 'accessible' to another iff the first is possible according to the second [Salmon,N] |
Full Idea: A world w' is accessible to a consistent world w if and only if w' is possible in w. Being 'inaccessible to' or 'possible relative to' a consistent world is simply being possible according to that world, nothing more and nothing less. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
A reaction: More illuminating than just saying that w can 'see' w'. Accessibility is internal to worIds. It gives some connection to why we spend time examining modal logic. There is no more important metaphysical notion than what is possible according to actuality. |
14669 | For metaphysics, T may be the only correct system of modal logic [Salmon,N] |
Full Idea: Insofar as modal logic is concerned exclusively with the logic of metaphysical modality, ..T may well be the one and only (strongest) correct system of (first-order) propositional logic. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro) | |
A reaction: This contrasts sharply with the orthodox view, that S5 (or at the very least S4) is the correct system for metaphysics. |
14667 | System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N] |
Full Idea: Even the conventionally accepted system B, which is weaker than S5 and independent of S4, has not been adequately justified as a fallacy-free system of reasoning about what might have been. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro) |
14668 | In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N] |
Full Idea: The characteristic of B has the form φ⊃□◊φ. ...Even if these axioms are necessarily true, it seems logically possible for p to be true while the proposition that p is necessarily possible is at the same time false. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro) |
14692 | System B implies that possibly-being-realized is an essential property of the world [Salmon,N] |
Full Idea: Friends of B modal logic commit themselves to the loaded claim that it is logically true that the property of possibly being realized (or being a way things might have been) is an essential property of the world. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], V) | |
A reaction: I think this 'loaded' formulation captures quite nicely the dispositional view I favour, that the possibilities of the actual world are built into the actual world, and define its nature just as much as the 'categorial' facts do. |
14671 | What is necessary is not always necessarily necessary, so S4 is fallacious [Salmon,N] |
Full Idea: We can say of a wooden table that it would have been possible for it to have originated from some different matter, even though it is not actually possible. So what is necessary fails to be necessarily necessary, and S4 modal logic is fallacious. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], I) | |
A reaction: [compressed] |
14686 | S5 modal logic ignores accessibility altogether [Salmon,N] |
Full Idea: When we ignore accessibility altogether, we have finally zeroed in on S5 modal logic. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) |
14691 | S5 believers say that-things-might-have-been-that-way is essential to ways things might have been [Salmon,N] |
Full Idea: Believers in S5 as a correct system of propositional reasoning about what might have been must claim that it is an essential property of any way things might have been that things might have been that way. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], V) | |
A reaction: Salmon is working in a view where you are probably safe to substitute 'necessary' for 'essential' without loss of meaning. |
14693 | The unsatisfactory counterpart-theory allows the retention of S5 [Salmon,N] |
Full Idea: Counterpart-theoretic modal semantics allows for the retention of S5 modal propositional logic, at a considerable cost. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], V n18) | |
A reaction: See the other ideas in this paper by Salmon for his general attack on S5 as the appropriate system for metaphysical necessity. He favours the very modest System T. |
14670 | Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N] |
Full Idea: Metaphysical modal logic concerns metaphysical (or alethic) necessity and metaphysical (alethic) possibility, or necessity and possibility tout court - as opposed to such other types of modality as physical necessity, epistemic necessity etc. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], Intro n2) |
16185 | Causality indicates which properties are real [Cartwright,N] |
Full Idea: Causality is a clue to what properties are real. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 9.3) | |
A reaction: An interesting variant on the Shoemaker proposal that properties actually are causal. I'm not sure that there is anything more to causality that the expression in action of properties, which I take to be powers. Structures are not properties. |
14678 | Any property is attached to anything in some possible world, so I am a radical anti-essentialist [Salmon,N] |
Full Idea: By admitting possible worlds of unlimited variation and recombination, I simply abandon true metaphysical essentialism. By my lights, any property is attached to anything in some possible world or other. I am a closet radical anti-essentialist. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], II) | |
A reaction: Salmon includes impossible worlds within his scheme of understanding. It strikes me that this is metaphysical system which tells us nothing about how things are: it is sort of 'logical idealist'. Later he talks of 'we essentialists'. |
14680 | Logical possibility contains metaphysical possibility, which contains nomological possibility [Salmon,N] |
Full Idea: Just as nomological possibility is a special kind of metaphysical possibility, so metaphysical possibility is a special kind of logical possibility. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
A reaction: This is the standard view of how the three types of necessity are nested. He gives a possible counterexample in footnote 7. |
14690 | In the S5 account, nested modalities may be unseen, but they are still there [Salmon,N] |
Full Idea: The S5 theorist's miscontrual of English (in the meaning of 'possibly possible') makes nested modality unseen, but it does not make nested modality vanish. Inaccessible worlds are still worlds. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) |
14677 | Metaphysical necessity is said to be unrestricted necessity, true in every world whatsoever [Salmon,N] |
Full Idea: It is held that it is the hallmark of metaphysical necessity is that it is completely unrestricted, the limiting case of restricted necessity, with no restrictions whatever. A proposition is necessary only if it is true in absolutely every world whatever. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], II) | |
A reaction: This is the standard picture which leads to the claim that S5 modal logic is appropriate for metaphysical necessity, because there are no restrictions on accessibility. Salmon raises objections to this conventional view. |
14679 | Bizarre identities are logically but not metaphysically possible, so metaphysical modality is restricted [Salmon,N] |
Full Idea: Though there is a way things logically could be according to which I am a credit card account, there is no way things metaphysically might be according to which I am a credit card account. This illustrates the restricted nature of metaphysical modality. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
A reaction: His drift is that metaphyical modality is restricted, but expressing it in S5 modal logic (where all worlds see one another) makes it unrestricted, so S5 logic is wrong for metaphysics. I'm impressed by his arguments. |
14688 | Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic [Salmon,N] |
Full Idea: If one confines one's sights to genuinely possible worlds, disavowing the impossible worlds, then metaphysical modality emerges as the limiting case - the 'unrestricted' modality that takes account of 'every' world - and S5 emerges as its proper logic. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
A reaction: He observes that this makes metaphysical modality 'restricted' simply because you have restricted what 'all worlds' means. Could there be non-maximal worlds? Are logical and metaphysical modality coextensive? I think I like the S5 view. |
14685 | Metaphysical necessity is NOT truth in all (unrestricted) worlds; necessity comes first, and is restricted [Salmon,N] |
Full Idea: A mythology gave us the idea that metaphysical necessity is truth in every world whatsoever, without restriction. But the notion of metaphysical modality comes first, and, like every notion of modality, it is restricted. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) |
14681 | Logical necessity is free of constraints, and may accommodate all of S5 logic [Salmon,N] |
Full Idea: With its freedom from the constraint of metaphysical possibility, logical necessity may be construed as accommodating all the axioms and rules of S5. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
A reaction: He goes on to raise problems for this simple thought. The big question: what are the limits of what is actually possible? Compare: what are the limits of what is imaginable? what are the limits of what is meaningfully sayable? |
14676 | Nomological necessity is expressed with intransitive relations in modal semantics [Salmon,N] |
Full Idea: Intransitive relations are introduced into modal semantics for the purposes of interpreting various 'real' or restricted types of modalities, such as nomological necessity. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], II) | |
A reaction: The point here is that the (so-called) 'laws of nature' are held to change from world to world, so necessity in one could peter out in some more remote world, rather than being carried over everywhere. A very Humean view of such things. |
14689 | Necessity and possibility are not just necessity and possibility according to the actual world [Salmon,N] |
Full Idea: The real meanings of the simple modal terms 'necessary' and 'possible' are not the same as the concepts of actual necessity and actual possibility, necessity and possibility according to the actual world. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
A reaction: If you were an 'actualist' (who denies everything except the actual world) then you are unlikely to agree with this. In unrestricted possible worlds, being true in one world makes it possible in all worlds. So actual necessity is possible everywhere. |
14674 | Impossible worlds are also ways for things to be [Salmon,N] |
Full Idea: Total ways things cannot be are also 'worlds', or maximal ways for things to be. They are impossible worlds. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], I) | |
A reaction: This unorthodox view doesn't sound too plausible to me. To think of a circular square as a 'way things could be' sounds pretty empty, and mere playing with words. The number 7 could be the Emperor of China? |
14682 | Denial of impossible worlds involves two different confusions [Salmon,N] |
Full Idea: Every argument I am aware of against impossible worlds confuses ways for things to be with ways things might have been, or worse, confuses ways things cannot be with ways for things to be that cannot exist - or worse yet, commits both errors. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], III) | |
A reaction: He is claiming that 'ways for things to be' allows impossible worlds, whereas 'ways things might have been' appears not to. (I think! Read the paragraph yourself!) |
14687 | Without impossible worlds, how things might have been is the only way for things to be [Salmon,N] |
Full Idea: If one ignores impossible worlds, then ways things might have been are the only ways for things to be that are left. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
A reaction: Impossible worlds are included in 'ways for things to be', but excluded from 'ways things might have been'. I struggle with a circle being square as a 'way for circles to be'. I suppose being the greatest philosopher is a way for me to be. |
14683 | Possible worlds rely on what might have been, so they can' be used to define or analyse modality [Salmon,N] |
Full Idea: On my conception, the notions of metaphysical necessity and possibility are not defined or analyzed in terms of the apparatus of possible worlds. The order of analysis is just the reverse: possible worlds rely on the notion of what might have been. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], IV) | |
A reaction: This view seems to be becoming the new orthodoxy, and I certainly agree with it. I have no idea how you can begin to talk about possible worlds if you don't already have some idea of what 'possible' means. |
14672 | Possible worlds are maximal abstract ways that things might have been [Salmon,N] |
Full Idea: I conceive of possible worlds as certain sorts of maximal abstract entities according to which certain things (facts, states of affairs) obtain and certain other things do not obtain. They are total ways things might have been. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], I) |
14675 | Possible worlds just have to be 'maximal', but they don't have to be consistent [Salmon,N] |
Full Idea: As far as I can tell, worlds need not be logically consistent. The only restriction on worlds is that they must be (in some sense) 'maximal' ways for things to be. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], I) | |
A reaction: The normal idea of a maximal model is that it must contain either p or ¬p, and not both, so I don't think I understand this thought, but I pass it on. |
14673 | You can't define worlds as sets of propositions, and then define propositions using worlds [Salmon,N] |
Full Idea: It is not a good idea to think of possible worlds as sets of propositions, and at the same time to think of propositions as sets of possible worlds. | |
From: Nathan Salmon (The Logic of What Might Have Been [1989], I n3) | |
A reaction: Salmon favours thinking of worlds as sets of propositions, and hence rejects the account of propositions as sets of worlds. He favours the 'Russellian' view of propositions, which seem to me to be the same as 'facts'. |
16182 | Two main types of explanation are by causes, or by citing a theoretical framework [Cartwright,N] |
Full Idea: In explaining a phenomenon one can cite the causes of that phenomenon; or one can set the phenomenon in a general theoretical framework. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 4.1) | |
A reaction: The thing is, you need to root an explanation in something taken as basic, and theoretical frameworks need further explanation, whereas causes seem to be basic. |
16184 | An explanation is a model that fits a theory and predicts the phenomenological laws [Cartwright,N] |
Full Idea: To explain a phenomenon is to find a model that fits it into the basic framework of the theory and that thus allows us to derive analogues for the messy and complicated phenomenological laws that are true of it. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 8.3) | |
A reaction: This summarises the core of her view in this book. She is after models rather than laws, and the models are based on causes. |
16167 | Laws get the facts wrong, and explanation rests on improvements and qualifications of laws [Cartwright,N] |
Full Idea: We explain by ceteris paribus laws, by composition of causes, and by approximations that improve on what the fundamental laws dictate. In all of these cases the fundamental laws patently do not get the facts right. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], Intro) | |
A reaction: It is rather headline-grabbing to say in this case that laws do not get the facts right. If they were actually 'wrong' and 'lied', there wouldn't be much point in building explanations on them. |
16169 | Laws apply to separate domains, but real explanations apply to intersecting domains [Cartwright,N] |
Full Idea: When different kinds of causes compose, we want to explain what happens in the intersection of different domains. But the laws we use are designed only to tell truly what happens in each domain separately. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], Intro) | |
A reaction: Since presumably the laws are discovered through experiments which try to separate out a single domain, in those circumstances they actually are true, so they don't 'lie'. |
16176 | Covering-law explanation lets us explain storms by falling barometers [Cartwright,N] |
Full Idea: Much criticism of the original covering-law model objects that it lets in too much. It seems we can explain Henry's failure to get pregnant by his taking birth control pills, and we can explain the storm by the falling barometer. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 2.0) | |
A reaction: I take these examples to show that true explanations must be largely causal in character. The physicality of causation is what matters, not 'laws'. I'd say the same of attempts to account for causation through counterfactuals. |
16177 | I disagree with the covering-law view that there is a law to cover every single case [Cartwright,N] |
Full Idea: Covering-law theorists tend to think that nature is well-regulated; in the extreme, that there is a law to cover every case. I do not. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 2.2) | |
A reaction: The problem of coincidence is somewhere at the back of this thought. Innumerable events have their own explanations, but it is hard to explain their coincidence (see Aristotle's case of bumping into a friend in the market). |
16180 | You can't explain one quail's behaviour by just saying that all quails do it [Cartwright,N] |
Full Idea: 'Why does that quail in the garden bob its head up and down in that funny way whenever it walks?' …'Because they all do'. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 3.5) | |
A reaction: She cites this as an old complaint against the covering-law model of explanation. It captures beautifully the basic error of the approach. We want to know 'why', rather than just have a description of the pattern. 'They all do' is useful information. |
16171 | The covering law view assumes that each phenomenon has a 'right' explanation [Cartwright,N] |
Full Idea: The covering-law account supposes that there is, in principle, one 'right' explanation for each phenomenon. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], Intro) | |
A reaction: Presumably the law is held to be 'right', but there must be a bit of flexibility in describing the initial conditions, and the explanandum itself. |
16183 | In science, best explanations have regularly turned out to be false [Cartwright,N] |
Full Idea: There are a huge number of cases in the history of science where we now know our best explanations were false. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 5.3) | |
A reaction: [She cites Laudan 1981 for this] The Ptolemaic system and aether are the standard example cited for this. I believe strongly in the importance of best explanation. Only a fool would just accept the best explanation available. Coherence is needed. |
16175 | A cause won't increase the effect frequency if other causes keep interfering [Cartwright,N] |
Full Idea: A cause ought to increase the frequency of the effect, but this fact may not show up in the probabilities if other causes are at work. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 1.1) | |
A reaction: [She cites Patrick Suppes for this one] Presumably in experimental situations you can weed out the interference, but that threatens to eliminate mere 'probability' entirely. |
6781 | There are fundamental explanatory laws (false!), and phenomenological laws (regularities) [Cartwright,N, by Bird] |
Full Idea: Nancy Cartwright distinguishes between 'fundamental explanatory laws', which we should not believe, and 'phenomenological laws', which are regularities established on the basis of observation. | |
From: report of Nancy Cartwright (How the Laws of Physics Lie [1983]) by Alexander Bird - Philosophy of Science Ch.4 | |
A reaction: The distinction is helpful, so that we can be clearer about what everyone is claiming. We can probably all agree on the phenomenological laws, which are epistemological. Personally I claim truth for the best fundamental explanatory laws. |
16166 | Laws of appearances are 'phenomenological'; laws of reality are 'theoretical' [Cartwright,N] |
Full Idea: Philosophers distinguish phenomenological from theoretical laws. Phenomenological laws are about appearances; theoretical ones are about the reality behind the appearances. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], Intro) | |
A reaction: I'm suspecting that Humeans only really believe in the phenomenological kind. I'm only interested in the theoretical kind, and I take inference to the best explanation to be the bridge between the two. Cartwright rejects the theoretical laws. |
16179 | Good organisation may not be true, and the truth may not organise very much [Cartwright,N] |
Full Idea: There is no reason to think that the principles that best organise will be true, nor that the principles that are true will organise much. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 2.5) | |
A reaction: This is aimed at the Mill-Ramsey-Lewis account of laws, as axiomatisations of the observed patterns in nature. |
16170 | To get from facts to equations, we need a prepared descriptions suited to mathematics [Cartwright,N] |
Full Idea: To get from a detailed factual knowledge of a situation to an equation, we must prepare the description of the situation to meet the mathematical needs of the theory. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], Intro) | |
A reaction: She is clearly on to something here, as Galileo is blatantly wrong in his claim that the book of nature is written in mathematics. Mathematics is the best we can manage in getting a grip on the chaos. |
16181 | Simple laws have quite different outcomes when they act in combinations [Cartwright,N] |
Full Idea: For explanation simple laws must have the same form when they act together as when they act singly. ..But then what the law states cannot literally be true, for the consequences that occur if it acts alone are not what occurs when they act in combination. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 3.6) | |
A reaction: This is Cartwright's basic thesis. Her point is that the laws 'lie', because they claim to predict a particular outcome which never ever actually occurs. She says we could know all the laws, and still not be able to explain anything. |
16178 | There are few laws for when one theory meets another [Cartwright,N] |
Full Idea: Where theories intersect, laws are usually hard to come by. | |
From: Nancy Cartwright (How the Laws of Physics Lie [1983], 2.3) | |
A reaction: There are attempts at so-called 'bridge laws', to get from complex theories to simple ones, but her point is well made about theories on the same 'level'. |
15313 | By 'force' I mean the sources of all actions - sometimes called 'powers' by their outcomes [Breheny] |
Full Idea: I mean by the word 'force' the source or sources of all possible actions of the particles or materials of the universe: these being often called the powers of nature when spoken of in relation to the different manners in which their effects are shown. | |
From: Richard Breheny (Letter to Clerk Maxwell [1855]), quoted by Harré,R./Madden,E.H. - Causal Powers 9.II.B | |
A reaction: He uses 'force' for what is fundamental, and 'powers' for their results. I am inclining to talk of 'fundamental powers' and 'complex powers', leaving the word 'force' to the physicists. |