27 ideas
| 5750 | Consistency is modal, saying propositions are consistent if they could be true together [Melia] |
| Full Idea: Consistency is a modal notion: a set of propositions is consistent iff all the members of the set could be true together. | |
| From: Joseph Melia (Modality [2003], Ch.6) | |
| A reaction: This shows why Kantian ethics, for example, needs a metaphysical underpinning. Maybe Kant should have believed in the reality of Leibnizian possible worlds? An account of reason requires an account of necessity and possibility. |
| 5737 | Predicate logic has connectives, quantifiers, variables, predicates, equality, names and brackets [Melia] |
| Full Idea: First-order predicate language has four connectives, two quantifiers, variables, predicates, equality, names, and brackets. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: Look up the reference for the details! The spirit of logic is seen in this basic framework, and the main interest is in the ontological commitment of the items on the list. The list is either known a priori, or it is merely conventional. |
| 5744 | First-order predicate calculus is extensional logic, but quantified modal logic is intensional (hence dubious) [Melia] |
| Full Idea: First-order predicate calculus is an extensional logic, while quantified modal logic is intensional (which has grave problems of interpretation, according to Quine). | |
| From: Joseph Melia (Modality [2003], Ch.3) | |
| A reaction: The battle is over ontology. Quine wants the ontology to stick with the values of the variables (i.e. the items in the real world that are quantified over in the extension). The rival view arises from attempts to explain necessity and counterfactuals. |
| 5740 | Second-order logic needs second-order variables and quantification into predicate position [Melia] |
| Full Idea: Permitting quantification into predicate position and adding second-order variables leads to second-order logic. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: Often expressed by saying that we now quantify over predicates and relations, rather than just objects. Depends on your metaphysical commitments. |
| 5741 | If every model that makes premises true also makes conclusion true, the argument is valid [Melia] |
| Full Idea: In first-order predicate calculus validity is defined thus: an argument is valid iff every model that makes the premises of the argument true also makes the conclusion of the argument true. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: See Melia Ch. 2 for an explanation of a 'model'. Traditional views of validity tend to say that if the premises are true the conclusion has to be true (necessarily), but this introduces the modal term 'necessarily', which is controversial. |
| 5735 | Maybe names and predicates can capture any fact [Melia] |
| Full Idea: Some philosophers think that any fact can be captured in a language containing only names and predicates. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: The problem case Melia is discussing is modal facts, such as 'x is possible'. It is hard to see how 'possible' could be an ordinary predicate, but then McGinn claims that 'existence' is, and that there are some predicates with unusual characters. |
| 5736 | No sort of plain language or levels of logic can express modal facts properly [Melia] |
| Full Idea: Some philosophers say that modal facts cannot be expressed either by name/predicate language, or by first-order predicate calculus, or even by second-order logic. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: If 'possible' were a predicate, none of this paraphernalia would be needed. If possible worlds are accepted, then the quantifiers of first-order predicate calculus will do the job. If neither of these will do, there seems to be a problem. |
| 16235 | Persistence conditions cannot contradict, so there must be a 'dominant sortal' [Burke,M, by Hawley] |
| Full Idea: Burke says a single object cannot have incompatible persistence conditions, for this would entail that there are events in which the object would both survive and perish. He says one sortal 'dominates' the other (sweater dominates thread). | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Katherine Hawley - How Things Persist 5.3 | |
| A reaction: This I take to be the most extreme version of sortal essentialism, and strikes me as incredibly gerrymandered and unacceptable. It is just too anthropocentric to count as genuine metaphysics. I may care more about the thread. |
| 14753 | The 'dominant' of two coinciding sortals is the one that entails the widest range of properties [Burke,M, by Sider] |
| Full Idea: Burke claims that the 'dominant' sortal is the one whose satisfaction entails possession of the widest range of properties. For example, the statue (unlike the lump of clay) also possesses aesthetic properties, and hence is dominant. | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Theodore Sider - Four Dimensionalism 5.4 | |
| A reaction: [there are three papers by Burke on this; see all the quotations from Burke] Presumably one sortal could entail a single very important property, and the other sortal entail a huge range of trivial properties. What does being a 'thing' entail? |
| 16072 | 'The rock' either refers to an object, or to a collection of parts, or to some stuff [Burke,M, by Wasserman] |
| Full Idea: Burke distinguishes three different readings of 'the rock'. It can be a singular description denoting an object, or a plural description denoting all the little pieces of rock, or a mass description the relevant rocky stuff. | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Ryan Wasserman - Material Constitution 5 | |
| A reaction: Idea 16068 is an objection to the second reading. Only the first reading seems plausible, so we must just get over all the difficulties philosophers have unearthed about knowing exactly what an 'object' is. I offer you essentialism. Rocks have unity. |
| 14751 | Tib goes out of existence when the tail is lost, because Tib was never the 'cat' [Burke,M, by Sider] |
| Full Idea: Burke argues that Tib (the whole cat apart from its tail) goes out of existence when the tail is lost. His essentialist principle is that if something is ever of a particular sort (such as 'cat') then it is always of that sort. Tib is not initially a cat. | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Theodore Sider - Four Dimensionalism 5.4 | |
| A reaction: This I take to be a souped up version of Wiggins, and I just don't buy that identity conditions are decided by sortals, when it seems obvious that sortals are parasitic on identities. |
| 16071 | Sculpting a lump of clay destroys one object, and replaces it with another one [Burke,M, by Wasserman] |
| Full Idea: On Burke's view, the process of sculpting a lump of clay into a statue destroys one object (a mere lump of clay) and replaces it with another (a statue). | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Ryan Wasserman - Material Constitution 5 | |
| A reaction: There is something right about this, but how many intermediate objects are created during the transition. It seems to make the notion of an object very conventional. |
| 16234 | Burke says when two object coincide, one of them is destroyed in the process [Burke,M, by Hawley] |
| Full Idea: Michael Burke argues that a sweater is identical with the thread that consitutes it, that both were created at the moment when they began to coincide, and that the original thread was destroyed in the process. | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Katherine Hawley - How Things Persist 5.3 | |
| A reaction: [Burke's ideas are spread over three articles] It is the thread which is destroyed, because the sweater is the 'dominant sortal' (which strikes me as a particularlyd desperate concept). |
| 13278 | Maybe the clay becomes a different lump when it becomes a statue [Burke,M, by Koslicki] |
| Full Idea: Burke has argued in a series of papers that the lump of clay which constitutes the statue is numerically distinct from the lump of clay which exists before or after the statue exists. The first is a statue, while the second is merely a lump of clay. | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Kathrin Koslicki - The Structure of Objects | |
| A reaction: Koslicki objects that this introduces radically different persistence conditions from normal. It would mean that a pile of sugar was a different pile of sugar every time a grain moved (even slightly). You couldn't step into the same sugar twice. |
| 14750 | Two entities can coincide as one, but only one of them (the dominant sortal) fixes persistence conditions [Burke,M, by Sider] |
| Full Idea: Michael Burke has given an account that avoids distinguishing coinciding entities. ...The statue/lump satisfies both 'lump' and 'statue', but only the latter determines that object's persistence conditions, and so is that object's 'dominant sortal'. | |
| From: report of Michael Burke (Dion and Theon: an essentialist solution [1994]) by Theodore Sider - Four Dimensionalism 5.4 | |
| A reaction: Presumably a lump on its own can have its own persistance conditions (as a 'lump'), but those would presumably be lost if you shaped it into a statue. Burke concedes that. Can of worms. Using a book as a doorstop... |
| 5746 | The Identity of Indiscernibles is contentious for qualities, and trivial for non-qualities [Melia] |
| Full Idea: If the Identity of Indiscernibles is referring to qualitative properties, such as 'being red' or 'having mass', it is contentious; if it is referring to non-qualitative properties, such as 'member of set s' or 'brother of a', it is true but trivial. | |
| From: Joseph Melia (Modality [2003], Ch.3 n 11) | |
| A reaction: I would say 'false' rather than 'contentious'. No one has ever offered a way of distinguishing two electrons, but that doesn't mean there is just one (very busy) electron. The problem is that 'indiscernible' is only an epistemological concept. |
| 5738 | We may be sure that P is necessary, but is it necessarily necessary? [Melia] |
| Full Idea: We may have fairly firm beliefs as to whether or not P is necessary, but many of us find ourselves at a complete loss when wondering whether or not P is necessarily necessary. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: I think it is questions like this which are pushing philosophy back towards some sort of rationalism. See Idea 3651, for example. A regress of necessities would be mad, so necessity must be taken as self-evident (in itself, though maybe not to us). |
| 5732 | 'De re' modality is about things themselves, 'de dicto' modality is about propositions [Melia] |
| Full Idea: In cases of 'de re' modality, it is a particular thing that has the property essentially or accidentally; where the modality attaches to the proposition, it is 'de dicto' - it is the whole truth that all bachelors are unmarried that is necessary. | |
| From: Joseph Melia (Modality [2003], Ch.1) | |
| A reaction: This seems to me one of the most important distinctions in metaphysics (as practised by analytical philosophers, who like distinctions). The first type leads off into the ontology, the second type veers towards epistemology. |
| 5739 | Sometimes we want to specify in what ways a thing is possible [Melia] |
| Full Idea: Sometimes we want to count the ways in which something is possible, or say that there are many ways in which a certain thing is possible. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: This is a basic fact about talk of 'possibility'. It is not an all-or-nothing property of a situation. There can be 'faint' possibilities of things. The proximity of some possible worlds, especially those sharing our natural laws, is one answer. |
| 5734 | Possible worlds make it possible to define necessity and counterfactuals without new primitives [Melia] |
| Full Idea: In modal logic the concepts of necessity and counterfactuals are not interdefinable, so the language needs two primitives to represent them, but with the machinery of possible worlds they are defined by what is the case in all worlds, or close worlds. | |
| From: Joseph Melia (Modality [2003], Ch.1) | |
| A reaction: If your motivation is to reduce ontology to the barest of minimums (which it was for David Lewis) then it is paradoxical that the existence of possible worlds may be the way to achieve it. I doubt, though, whether a commitment to their reality is needed. |
| 5742 | In possible worlds semantics the modal operators are treated as quantifiers [Melia] |
| Full Idea: The central idea in possible worlds semantics is that the modal operators are treated as quantifiers. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: It seems an essential requirement of metaphysics that an account be given of possibility and necessity, and it is also a good dream to keep the ontology simple. Commitment to possible worlds is the bizarre outcome of this dream. |
| 5743 | If possible worlds semantics is not realist about possible worlds, logic becomes merely formal [Melia] |
| Full Idea: It has proved difficult to justify possible worlds semantics without accepting possible worlds. Without a secure metaphysical underpinning, the results in logic are in danger of having nothing more than a formal significance. | |
| From: Joseph Melia (Modality [2003], Ch.2) | |
| A reaction: This makes nicely clear why Lewis's controversial modal realism has to be taken seriously. It appears that the key problem is truth, because that is needed to define validity, but you can't have truth without some sort of metaphysics. |
| 5749 | Possible worlds could be real as mathematics, propositions, properties, or like books [Melia] |
| Full Idea: One can be a realist about possible worlds without adopting Lewis's extreme views; they might be abstract or mathematical entities; they might be sets of propositions or maximal uninstantiated properties; they might be like books or pictures. | |
| From: Joseph Melia (Modality [2003], Ch.6) | |
| A reaction: My intuition is that once you go down the road of realism about possible worlds, Lewis's full concrete realism looks at least as attractive as any of these options. You can discuss the 'average man' in an economic theory without realism. |
| 5751 | The truth of propositions at possible worlds are implied by the world, just as in books [Melia] |
| Full Idea: Propositions are true at possible worlds in much the same way as they are true at books: by being implied by the book. | |
| From: Joseph Melia (Modality [2003], Ch.7) | |
| A reaction: An intriguing way to introduce the view that possible worlds should be seen as like books. The truth-makers of propositions about the actual world are items in it, but the truth-makers in novels (say) are the conditions of the whole work as united. |
| 5748 | We accept unverifiable propositions because of simplicity, utility, explanation and plausibility [Melia] |
| Full Idea: Many philosophers now concede that it is rational to accept a proposition not because we can directly verify it but because it is supported by considerations of simplicity, theoretical utility, explanatory power and/or intuitive plausibility. | |
| From: Joseph Melia (Modality [2003], Ch.5) | |
| A reaction: This suggests how the weakness of logical positivism may have led us to the concept of epistemic virtues (such as those listed), which are, of course, largely a matter of community consensus, just as the moral virtues are. |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |