49 ideas
18889 | Ostensive definitions needn't involve pointing, but must refer to something specific [Salmon,N] |
Full Idea: So-called ostensive definitions need not literally involve ostension, e.g. pointing, but they must involve genuine reference of some sort (in this case reference to a sample of water). | |
From: Nathan Salmon (Reference and Essence (1st edn) [1981], 4.11.2) |
19504 | My modus ponens might be your modus tollens [Pritchard,D] |
Full Idea: One philosopher's modus ponens is another philosopher's modus tollens. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§2) | |
A reaction: [Anyone know the originator of this nice thought?] You say A is true, and A proves B, so B is true. I reply that if A proves something as daft as B, then so much the worse for A. Ain't it the truth? |
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] |
14627 | S4, and therefore S5, are invalid for metaphysical modality [Salmon,N, by Williamson] |
Full Idea: Salmon argues that S4 and therefore S5 are invalid for metaphysical modality. | |
From: report of Nathan Salmon (Reference and Essence (1st edn) [1981], 238-40) by Timothy Williamson - Modal Logic within Counterfactual Logic 4 | |
A reaction: [He gives references for Salmon, and for his own reply] Salmon's view seems to be opposed my most modern logicians (such as Ian Rumfitt). |
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) |
14742 | It can't be indeterminate whether x and y are identical; if x,y is indeterminate, then it isn't x,x [Salmon,N] |
Full Idea: Insofar as identity seems vague, it is provably mistaken. If it is vague whether x and y are identical (as in the Ship of Theseus), then x,y is definitely not the same as x,x, since the first pair is indeterminate and the second pair isn't. | |
From: Nathan Salmon (Reference and Essence: seven appendices [2005], App I) | |
A reaction: [compressed; Gareth Evans 1978 made a similar point] This strikes me as begging the question in the Ship case, since we are shoehorning the new ship into either the slot for x or the slot for y, but that was what we couldn’t decide. No rough identity? |
18888 | Essentialism says some properties must be possessed, if a thing is to exist [Salmon,N] |
Full Idea: The metaphysical doctrine of essentialism says that certain properties of things are properties that those things could not fail to have, except by not existing. | |
From: Nathan Salmon (Reference and Essence (1st edn) [1981], 3.8.2) | |
A reaction: A bad account of essentialism, and a long way from Aristotle. It arises from the logicians' tendency to fix objects entirely in terms of a 'flat' list of predicates (called 'properties'!), which ignore structure, constitution, history etc. |
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. |
19503 | An improbable lottery win can occur in a nearby possible world [Pritchard,D] |
Full Idea: Low probability events such as lottery wins can occur in nearby possible worlds. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.n2) | |
A reaction: This seems to ruin any chance of mapping probabilities and counterfactuals in the neat model of nested possible worlds (like an onion). [Lewis must have thought of this, surely? - postcards, please] |
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'. |
19505 | Moore begs the question, or just offers another view, or uses 'know' wrongly [Pritchard,D, by PG] |
Full Idea: The three main objections to Moore's common-sense refutation of scepticism is that it either begs the question, or it just offers a rival view instead of a refutation, or it uses 'know' in a conversationally inappropriate way. | |
From: report of Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§2) by PG - Db (ideas) | |
A reaction: [I deserve applause for summarising two pages of Pritchard's wordy stuff so neatly] |
19499 | We can have evidence for seeing a zebra, but no evidence for what is entailed by that [Pritchard,D] |
Full Idea: The closure principle forces us to regard Zula as knowing that what she is looking at is not a cleverly disguised mule, and yet she doesn't appear to have any supporting evidence for this knowledge. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§3) | |
A reaction: [Zula observes a zebra in the zoo] Entailment is a different type of justification from perception. If we add fallibilism to the mix, then fallibility can increase as we pursue a string of entailments. But proper logic, of course, should not be fallible. |
19500 | Favouring: an entailment will give better support for the first belief than reason to deny the second [Pritchard,D] |
Full Idea: The Favouring Principle says that if S knows two things, and that the first entails the second, then S has better evidence in support of her belief in the first than she has for denying the second. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§3) | |
A reaction: [his version is full of Greek letters, but who wants that stuff?] Pritchard concludes that if you believe in the closure principle then you should deny the favouring principle. |
19502 | Maybe knowledge just needs relevant discriminations among contrasting cases [Pritchard,D] |
Full Idea: According to the 'contrastivist' proposal knowledge is to be understood as essentially involving discrimination, such that knowing a proposition boils down to having the relevant discriminatory capacities. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§6) | |
A reaction: Pritchard says this isn't enough, and we must also to be aware of supporting favouring evidence. I would focus on the concept of coherence, even for simple perceptual knowledge. If I see a hawk in England, that's fine. What if I 'see' a vulture? |
19498 | Epistemic internalism usually says justification must be accessible by reflection [Pritchard,D] |
Full Idea: Typically, internal epistemic conditions are characterised in terms of a reflective access requirement. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 1.§6) | |
A reaction: If your justification is straightforwardly visual, it is unclear what the difference would be between seeing the thing and having reflective access to the seeing. |
19506 | Externalism is better than internalism in dealing with radical scepticism [Pritchard,D] |
Full Idea: Standard epistemic internalism faces an uphill struggle when it comes to dealing with radical scepticism, which points in favour of epistemic externalist neo-Mooreanism. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§3) | |
A reaction: I incline towards internalism. I deal with scepticism by being a fallibilist, and adding 'but you never know' to every knowledge claim, and then getting on with life. |
19496 | Disjunctivism says perceptual justification must be both factual and known by the agent [Pritchard,D] |
Full Idea: Slogan for disjunctivism: perceptual knowledge is paradigmatically constituted by a true belief whose epistemic support is both factive (i.e. it entails the truth of the propositions believed) and reflectively accessible to the agent. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], Intro) | |
A reaction: I'm not a fan of externalism, but it could be that the factive bit achieves the knowledge, and then being able to use and answer for that knowledge may just be a bonus, and not an essential ingredient. |
19497 | Metaphysical disjunctivism says normal perceptions and hallucinations are different experiences [Pritchard,D] |
Full Idea: Metaphysical disjunctivists hold that veridical perceptual experiences are not essentially the same as the experiences involved in corresponding cases involving illusion and (especially) hallucination. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 1.§4) | |
A reaction: Metaphysical disjunctivism concerns what the experiences are; epistemological justification concerns the criteria of justification. I think. I wish Pritchard would spell things out more clearly. Indeed, I wish all philosophers would. |
19495 | Epistemic externalism struggles to capture the idea of epistemic responsibility [Pritchard,D] |
Full Idea: A fundamental difficulty for epistemic externalist positions is that it is hard on this view to capture any adequate notion of epistemic responsibility. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], Intro) | |
A reaction: He never explains the 'responsibility', but I presume that would be like an expert witness in court, vouching for their knowledge. |
19501 | We assess error against background knowledge, but that is just what radical scepticism challenges [Pritchard,D] |
Full Idea: When faced with an error-possibility we can appeal to background knowledge, as long as the error-possibility does not call into question this background knowledge. The same is not true when we focus on the radical sceptical hypothesis. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§5) | |
A reaction: [reworded] Doubting everything simultaneously just looks like a mad project. If you doubt linguistic meaning, you can't even express your doubts. |
19507 | Radical scepticism is merely raised, and is not a response to worrying evidence [Pritchard,D] |
Full Idea: Crucially, radical sceptical error-possibilities are never epistemically motivated, but are instead merely raised. | |
From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§5) | |
A reaction: In 'The Matrix' someone sees a glitch in the software (a cat crossing a passageway), and that would have to be taken seriously. Otherwise it is a nice strategy to ask why the sceptic is raising this bizzare possibility, without evidence. |
20653 | Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson] |
Full Idea: There are six 'reductive levels' in science: social groups, (multicellular) living things, cells, molecules, atoms, and elementary particles. | |
From: report of H.Putnam/P.Oppenheim (Unity of Science as a Working Hypothesis [1958]) by Peter Watson - Convergence 10 'Intro' | |
A reaction: I have the impression that fields are seen as more fundamental that elementary particles. What is the status of the 'laws' that are supposed to govern these things? What is the status of space and time within this picture? |
18886 | Frege's 'sense' solves four tricky puzzles [Salmon,N] |
Full Idea: Reference via sense solves Frege's four puzzles, of the informativeness of identity statements, the failure of substitutivity in attitude contexts, of negative existentials, and the truth-value of statements using nondenoting singular terms. | |
From: Nathan Salmon (Reference and Essence (1st edn) [1981], 1.1.1) | |
A reaction: These must then be compared with Kripke's three puzzles about referring via sense, and the whole debate is then spread before us. |
18887 | The perfect case of direct reference is a variable which has been assigned a value [Salmon,N] |
Full Idea: The paradigm of a nondescriptional, directly referential, singular term is an individual variable. …The denotation of a variable… is semantically determined directly by the assignment of values. | |
From: Nathan Salmon (Reference and Essence (1st edn) [1981], 1.1.2) | |
A reaction: This cuts both ways. Maybe we are muddling ordinary reference with the simplicities of logical assignments, or maybe we make logical assignments because that is the natural way our linguistic thinking works. |
18885 | Kripke and Putnam made false claims that direct reference implies essentialism [Salmon,N] |
Full Idea: Kripke and Putnam made unsubstantiated claims, indeed false claims, to the effect that the theory of direct reference has nontrivial essentialist import. | |
From: Nathan Salmon (Reference and Essence: seven appendices [2005], Pref to Exp Ed) | |
A reaction: Kripke made very few claims, and is probably innocent of the charge. Most people agree with Salmon that you can't derive metaphysics from a theory of reference. |
18891 | Nothing in the direct theory of reference blocks anti-essentialism; water structure might have been different [Salmon,N] |
Full Idea: There seems to be nothing in the theory of direct reference to block the anti-essentialist assertion that the substance water might have been the very same entity and yet have had a different chemical structure. | |
From: Nathan Salmon (Reference and Essence (1st edn) [1981], 6.23.1) | |
A reaction: Indeed, water could be continuously changing its inner structure, while retaining the surface appearance that gets baptised as 'water'. We make the reasonable empirical assumption, though, that structure-change implies surface-change. |