42 ideas
| 16440 | I don't think Lewis's cost-benefit reflective equilibrium approach offers enough guidance [Stalnaker] |
| Full Idea: Lewis articulated and made fashionable the cost-benefit reflective equilibrium methodology, but I have my reservations as it does not offer much guidance. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.1) | |
| A reaction: Stalnaker suggests that this approach has 'run amok' in Lewis's case, giving reality to possible worlds. He spends much effort on showing the 'benefits' of a profoundly implausible view. The same can be said of 4D Perdurantism. |
| 16468 | Non-S5 can talk of contingent or necessary necessities [Stalnaker] |
| Full Idea: One can make sense of necessary versus contingent necessities in a non-S5 modal semantics. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.3 n17) | |
| A reaction: In S5 □φ → □□φ, so all necessities are necessary. Does it make any sense to say 'I suppose this might have been necessarily true'? |
| 16449 | In modal set theory, sets only exist in a possible world if that world contains all of its members [Stalnaker] |
| Full Idea: One principle of modal set theory should be uncontroversial: a set exists in a given possible world if and only if all of its members exist at that world. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 2.4) | |
| A reaction: Does this mean there can be no set containing all of my ancestors and future descendants? In no world can we coexist. |
| 16464 | We regiment to get semantic structure, for evaluating arguments, and understanding complexities [Stalnaker] |
| Full Idea: The point of regimentation is to give a perspicuous representation of the semantic structure of an expression, making it easier to evaluate the validity of arguments and to interpret complex statements. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.2) | |
| A reaction: This is an authoritative summary from an expert of why all philosophers must take an interest in logical form. |
| 16465 | In 'S was F or some other than S was F', the disjuncts need S, but the whole disjunction doesn't [Stalnaker] |
| Full Idea: In 'either Socrates was a philosopher or someone other than Socrates was a philosopher', both propositions expressed by the disjuncts depend for their existence on the existence of Socrates, but the whole disjunction does not. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.2) | |
| A reaction: Nice example, just the sort of thing we pay philosophers to come up with. He is claiming that propositions can exist in possible worlds in which the individuals mentioned do not exist. |
| 20457 | Zeno assumes collecting an infinity of things makes an infinite thing [Rovelli] |
| Full Idea: One possible answer is that Zeno is wrong because it is not true that by accumulating an infinite number of things one ends up with an infinite thing. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 01) | |
| A reaction: I do love it when deep and complex ideas are expressed with perfect simplicity. As long as the simple version is correct. |
| 16434 | Some say what exists must do so, and nothing else could possible exist [Stalnaker] |
| Full Idea: Some philosophers deny there could have been anything other than what in fact exists, or that anything that exists could have failed to exist. This is developed in very different ways by Wittgenstein (in 'Tractatus'), Lewis and Williamson. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1) | |
| A reaction: This could come in various strengths. A weak version would say that, empirically, that all talk of what doesn't exist is vacuous. A strong necessity (Williamson?) that totally rules out other possible existence is a very odd view. |
| 16439 | A nominalist view says existence is having spatio-temporal location [Stalnaker] |
| Full Idea: A nominalist definition of existence is 'having spatio-temporal location'. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.1) | |
| A reaction: This would evidently be physicalist as well as nominalist. Presumably it fits the 'mosaic' of reality Lewis refers to. I find this view sympathetic. A process of abstraction is required to get the rest of the stuff we talk about. |
| 20468 | Quantum mechanics deals with processes, rather than with things [Rovelli] |
| Full Idea: Quantum mechanics teaches us not to think about the world in terms of 'things' which are in this or that state, but in terms of 'processes' instead. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) |
| 20467 | Quantum mechanics describes the world entirely as events [Rovelli] |
| Full Idea: The world of quantum mechanics is not a world of objects: it is a world of events. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) | |
| A reaction: I presume a philosopher is allowed to ask what an 'event' is. Since, as Rovelli tells it, time is eliminated from the picture, events seem to be unanalysable primitives. |
| 16443 | Properties are modal, involving possible situations where they are exemplified [Stalnaker] |
| Full Idea: I take properties and relations to be modal notions. Properties are to be understood in terms of what it would be for them to be exemplified, which means understanding them in terms of a range of possible situations. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.2) | |
| A reaction: I can't make head or tail of a property as anything other than a feature of some entity. Treating properties as a 'range of situations' is just as baffling to me as treating them as sets of objects. |
| 16471 | I accept a hierarchy of properties of properties of properties [Stalnaker] |
| Full Idea: I myself am prepared to accept higher-order properties and relations. There is the property of being Socrates, …and the property of being the property of being Socrates, ..and so on. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.4) | |
| A reaction: Elsewhere I have quoted such a hierarchy of vacuous properties as an absurdity that arises if all predicates are treated as properties. Logicians can live with such stuff, given their set hierarchy and so on, but in science and life this is a nonsense. |
| 16452 | Dispositions have modal properties, of which properties things would have counterfactually [Stalnaker] |
| Full Idea: Dispositional properties deserve special mention since they seem to be properties that have modal consequences - consequences for what properties the individuals that instantiate them would have in counterfactual circumstances. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 3.4) | |
| A reaction: I take this to be the key idea in trying to understand modality, but Stalnaker makes this point and then moves swiftly on, because it is so far away from his possible worlds models, in which he has invested a lifetime. |
| 16467 | 'Socrates is essentially human' seems to say nothing could be Socrates if it was not human [Stalnaker] |
| Full Idea: It seems natural to paraphrase the claim that Socrates is essentially human as the claim that nothing could be Socrates if it was not human. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.3) | |
| A reaction: In ordinary speech it would be emphasising how very human Socrates was (in comparison with Frege, for example). By this token Socrates essentially breathes oxygen, but that is hardly part of his essence. |
| 16453 | The bundle theory makes the identity of indiscernibles a necessity, since the thing is the properties [Stalnaker] |
| Full Idea: On the bundle theory, the identity of indiscernibles (for 'individuals') is a necessary truth, since an individual is just the co-instantiation of all the properties represented by a point in the space of properties. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 3.6) | |
| A reaction: So much the worse for the bundle theory, I presume. Leibniz did not, I think, hold a bundle theory, but his belief in the identity of indiscernibles seems to have had a theologicial underpinning. |
| 16466 | Strong necessity is always true; weak necessity is cannot be false [Stalnaker] |
| Full Idea: Prior had a strong and a weak reading of necessity, where strong necessity is truth in all possible worlds, while weak necessity is falsity in no possible world. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4.3) | |
| A reaction: [K.Fine 2005:Ch.9 is also cited] The point of the weak one is that in some worlds there might not exist the proposition which is the candidate for truth or falsehood. |
| 16438 | Necessity and possibility are fundamental, and there can be no reductive analysis of them [Stalnaker] |
| Full Idea: My view is that if there were a nonmodal analysis of the modal concepts, that would be a sure sign that we were on the wrong track. Necessity and possibility are fundamental concepts, like truth and existence. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.1) | |
| A reaction: The mystery of modality is tied up with the mystery of time (which is a very big mystery indeed). You get a nice clear grip on the here and now, but time and motion whisk you away to something else. Modality concerns the something else. |
| 16436 | Modal concepts are central to the actual world, and shouldn't need extravagant metaphysics [Stalnaker] |
| Full Idea: Modal concepts are central to our understanding of the world - the actual world - and understanding them should not require extravagant metaphysical commitments. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1) | |
| A reaction: I agree. Personally I think powers and dispositions do the job nicely. You just have to embrace Leibniz's emphasis on the active nature of reality, and the implausible metaphysics starts to recede. |
| 16433 | Given actualism, how can there be possible individuals, other than the actual ones? [Stalnaker] |
| Full Idea: My main focus is on how, on an actualist interpretation of possible worlds as ways a world might be, one is to account for the possibility that there be individuals other than those that actually exist. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], Pref) | |
| A reaction: The obvious thought would be that they are constructions from components of actual individuals, such as the chimaera, or fictional characters. We need some psychology here, which is not Stalnaker's style. |
| 16437 | Possible worlds are properties [Stalnaker] |
| Full Idea: Possible worlds are (to a first approximation) properties. [p.12] They are properties of the total universe. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1) |
| 16444 | Possible worlds don't reduce modality, they regiment it to reveal its structure [Stalnaker] |
| Full Idea: It is not reduction (of modality) but regimentation that the possible-worlds framework provides - a procedure for representing modal discourse, using primitive modal notions, in a way that helps reveal its structure. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.2) | |
| A reaction: I think this is exactly my view. All discussion of the ontology of possible worlds is irrelevant. They no more exist than variables in logic exist. They're good when they clarify, but dubious when they over-simplify. |
| 16445 | I think of worlds as cells (rather than points) in logical space [Stalnaker] |
| Full Idea: I prefer to think of the possible worlds not as points in logical space but as cells of a relatively fine-grained partition of logical space - a partition that makes all the distinctions we need. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.2) | |
| A reaction: Since he regards possible worlds as simply a means of regimenting our understanding of modality, he can think of possible worlds in any way that suits him. I find it hard work tuning in to his vision. |
| 16454 | Modal properties depend on the choice of a counterpart, which is unconstrained by metaphysics [Stalnaker] |
| Full Idea: Things have modal properties only relative to the choice of a counterpart relation, and the choice between alternative counterpart relations is not constrained by the metaphysics. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 3.6) | |
| A reaction: Stalnaker is sympathetic to counterparts, but this strikes me as a powerful objection to the theory. I take the modal properties of something to be fixed by its actuality. |
| 16450 | Anti-haecceitism says there is no more to an individual than meeting some qualitative conditions [Stalnaker] |
| Full Idea: The anti-haecceitist strategy holds that a purely qualitative characterisation of a possible world would be a complete characterisation; there is, on this view, nothing to being a particular individual other than meeting certain qualitative conditions. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 3) | |
| A reaction: Not quite the same as the bundle theory of objects, which says the objects are the qualities. This is about individuation, not about ontology (I think). I don't like anti-haecceitism, but I also don't like haecceitism. Hmm. |
| 16474 | How can we know what we are thinking, if content depends on something we don't know? [Stalnaker] |
| Full Idea: How can we know what we ourselves are thinking if the very existence of the content of our thought may depend on facts of which we are ignorant? | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 5) | |
| A reaction: This has always been my main doubt about externalism. I may defer to experts about what I intend by an 'elm' (Putnam's example), but what I mean by elm is thereby a fuzzy tall tree with indeterminate leaves. I don't know the meaning of 'elm'! |
| 16461 | We still lack an agreed semantics for quantifiers in natural language [Stalnaker] |
| Full Idea: We still do not know how to give a direct semantics for the quantifiers of a natural language; that is something that we still do not know how to do (or at least how it is done remains controversial). | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 4) | |
| A reaction: I am struck by how rapidly the domain of quantification changes, even in mid-sentence, in the course of an ordinary conversation. This is decided almost entirely by context, not by pure ('direct'?) semantics. |
| 16448 | Possible world semantics may not reduce modality, but it can explain it [Stalnaker] |
| Full Idea: Most theorists agree that possible worlds semantics cannot provide an analysis of modal concepts which is an eliminative reduction, but it can still provide an explanation of the meanings of modal expressions. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 2.2) | |
| A reaction: Stalnaker cites Kit Fine for the view that there is no reduction of modality, which Fine takes to be primitive. Stalnaker defends the semantics, while denying the reduction which Lewis thought possible. |
| 16442 | I take propositions to be truth conditions [Stalnaker] |
| Full Idea: I will defend the view that propositions are truth conditions. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 1.2) | |
| A reaction: This sounds close to the Russellian view, which I take to equate propositions (roughly) with facts or states of affairs. But are 'truth conditions' in the world or in the head? |
| 16447 | A theory of propositions at least needs primitive properties of consistency and of truth [Stalnaker] |
| Full Idea: A minimal theory of propositions can make do with just two primitive properties: a property of consistency applied to sets of propositions, and a property of truth applied to propositions. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 2) | |
| A reaction: I would have thought a minimal theory would need some account of what a proposition is supposed to be (since there seems to be very little agreement about that). Stalnaker goes on to sketch a theory. |
| 16446 | Propositions presumably don't exist if the things they refer to don't exist [Stalnaker] |
| Full Idea: It seems plausible that singular propositions are object-dependent in the sense that the proposition would not exist if the individual did not. It is also plausible that some objects exist contingently, and there are singular propositions about them. | |
| From: Robert C. Stalnaker (Mere Possibilities [2012], 2) | |
| A reaction: This replies to the view that possible worlds are maximal sets of propositions, and so must exist for the worlds to exist; e.g. Lowe 1999:248. That is yet another commonplace of contemporary philosophy which I find utterly bewildering. |
| 20469 | There are probably no infinities, and 'infinite' names what we do not yet know [Rovelli] |
| Full Idea: 'Infinite', ultimately, is the name that we give to what we do not yet know. Nature appears to be telling us that there is nothing truly infinite. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 11) |
| 19399 | Prime matter is nothing when it is at rest [Leibniz] |
| Full Idea: Primary matter is nothing if considered at rest. | |
| From: Gottfried Leibniz (Aristotle and Descartes on Matter [1671], p.90) | |
| A reaction: This goes with Leibniz's Idea 13393, that activity is the hallmark of existence. No one seems to have been able to make good sense of prime matter, and it plays little role in Aristotle's writings. |
| 20461 | The basic ideas of fields and particles are merged in quantum mechanics [Rovelli] |
| Full Idea: The notions of fields and particles, separated by Faraday and Maxwell, end up merging in quantum mechanics. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) | |
| A reaction: This sounds to me just like Anaximander's 'apeiron' - the unlimited [Rovelli agrees! p.168]. Anaximander predicted the wall which enquiry would hit, but we now have more detail. |
| 20462 | Because it is quantised, a field behaves like a set of packets of energy [Rovelli] |
| Full Idea: Since the energy of the electromagnetic field can take on only certain values, the field behaves like a set of packets of energy. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) |
| 20463 | There are about fifteen particles fields, plus a few force fields [Rovelli] |
| Full Idea: There are about fifteen fields, whose quanta are elementary particles (electrons, quarks, muons, neutrinos, Higgs, and little else), plus a few fields similar to the electromagnetic one, which describe forces at a nuclear scale, with quanta like photons. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) | |
| A reaction: According to Rovelli, this sentence describes the essence of physical reality. |
| 20464 | The world consists of quantum fields, with elementary events happening in spacetime [Rovelli] |
| Full Idea: The world is not made up of fields and particles, but of a single type of entity: the quantum field. There are no longer particles which move in space with the passage of time, but quantum fields whose elementary events happen in spacetime. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) | |
| A reaction: If you are not a scientist, there is (I find) a strong tendency to read and digest stuff like this, and then forget it the next day, because it so far from our experience. Folk like me have to develop two parallel views of the nature of reality. |
| 20459 | Electrons only exist when they interact, and their being is their combination of quantum leaps [Rovelli] |
| Full Idea: Electrons don't always exist. They exist when they interact. They materialize when they collide with something. The quantum leap from one orbit to another constitutes their way of being real. An electron is a combination of leaps between interactions. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) | |
| A reaction: If a philosopher with an Aristotelian interest in the nature of matter wants to grasp the modern view, the electron looks like the thing to focus on. You can feel Rovelli battling here to find formulations that might satisfy a philosopher. |
| 20460 | Electrons are not waves, because their collisions are at a point, and not spread out [Rovelli] |
| Full Idea: Schrödinger's wave is a bad image for an electron, because when a particle collides with something else, it is always at a point: it is never spread out in space like a wave. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04 note) | |
| A reaction: And yet there is the diffusion in the two-slit experiment, which Thomas Young discovered for light. I must take Rovelli's word for this. |
| 20466 | Quantum Theory describes events and possible interactions - not how things are [Rovelli] |
| Full Idea: Quantum Theory does not describe things as they are: it describes how things occur and interact with each other. It doesn't describe where there is a particle but how it shows itself to others. The world of existence is reduced to possible interactions. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) | |
| A reaction: Fans of 'process philosophy' should like this, though he is not denying that there may be facts about how things are - it is just that this is not mentioned in the theory. There is not much point in philosophers yearning to know the reality. |
| 20465 | Nature has three aspects: granularity, indeterminacy, and relations [Rovelli] |
| Full Idea: I think that quantum mechanics has revealed three aspects of the nature of things: granularity, indeterminacy, and the relational structure of the world. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 04) |
| 20458 | The world is just particles plus fields; space is the gravitational field [Rovelli] |
| Full Idea: The world is made up of particles + fields, and nothing else; there is no need to add space as an extra ingredient. Newton's space is the gravitational field. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 03) | |
| A reaction: I get the impression that particles are just bumps or waves in the fields [yes! Rovelli p.110], which would mean there are fields and nothing else. And no one seems to know what a field is. |
| 20470 | Only heat distinguishes past from future [Rovelli] |
| Full Idea: It is always heat and only heat that distinguishes the past from the future. | |
| From: Carlo Rovelli (Reality is Not What it Seems [2014], 12) | |
| A reaction: I can remember the past but not the future - so can that fact be reduced to facts about heat? |