21 ideas
| 14025 | The weaker version of Truthmaker: 'truth supervenes on being' [Crisp,TM] |
| Full Idea: The weaker version of Truthmaker is that 'truth supervenes on being'. | |
| From: Thomas M. Crisp (Presentism [2003], 3.4) | |
| A reaction: [He cites Lewis 2001 and Bigelow 1988] This still leaves the difficulty of truths about non-existent things, and truths about possibilities (esp. those that are possible, but are never actualised). What being do mathematical truths supervene on? |
| 14023 | The Truthmaker thesis spells trouble for presentists [Crisp,TM] |
| Full Idea: The Truthmaker thesis (that 'for every truth there is a truthmaker, that is, something whose very existence entails the truth' - Fox 1987) spells trouble for the presentist about time. | |
| From: Thomas M. Crisp (Presentism [2003], 3.4) | |
| A reaction: The point is that presentists can no longer express truths about the past (never mind the future), because the truthmakers for them don't exist. This seems to neglect the power of tense - the truth of the claim that 'p was true'. |
| 14024 | Truthmaker has problems with generalisation, non-existence claims, and property instantiations [Crisp,TM] |
| Full Idea: Truthmaker is controversial: what of truths like 'all ravens are black', or 'there are no unicorns'. And 'John is tall' is not made true by John or the property of being tall, but by the fusion of the two, but what could this non-mereological fusion be? | |
| From: Thomas M. Crisp (Presentism [2003], 3.4) | |
| A reaction: A first move is to include modal facts (or possible worlds) among the truthmakers. The unicorns are tricky, and seem to need all of actuality as their truthmaker. I don't see the tallness difficulty. Predication is odd, but so what? |
| 10653 | Maybe set theory need not be well-founded [Varzi] |
| Full Idea: There are some proposals for non-well-founded set theory (tolerating cases of self-membership and membership circularities). | |
| From: Achille Varzi (Mereology [2003], 2.1) | |
| A reaction: [He cites Aczel 1988, and Barwise and Moss 1996] |
| 10648 | Mereology need not be nominalist, though it is often taken to be so [Varzi] |
| Full Idea: While mereology was originally offered with a nominalist viewpoint, resulting in a conception of mereology as an ontologically parsimonious alternative to set theory, there is no necessary link between analysis of parthood and nominalism. | |
| From: Achille Varzi (Mereology [2003], 1) | |
| A reaction: He cites Lesniewski and Leonard-and-Goodman. Do you allow something called a 'whole' into your ontology, as well as the parts? He observes that while 'wholes' can be concrete, they can also be abstract, if the parts are abstract. |
| 10655 | Are there mereological atoms, and are all objects made of them? [Varzi] |
| Full Idea: It is an open question whether there are any mereological atoms (with no proper parts), and also whether every object is ultimately made up of atoms. | |
| From: Achille Varzi (Mereology [2003], 3) | |
| A reaction: Such a view would have to presuppose (metaphysically) that the divisibility of matter has limits. If one follows this route, then are there only 'natural' wholes, or are we 'unrestricted' in our view of how the atoms combine? I favour the natural route. |
| 10659 | There is something of which everything is part, but no null-thing which is part of everything [Varzi] |
| Full Idea: It is common in mereology to hold that there is something of which everything is part, but few hold that there is a 'null entity' that is part of everything. | |
| From: Achille Varzi (Mereology [2003], 4.1) | |
| A reaction: This comes out as roughly the opposite of set theory, which cannot do without the null set, but is not keen on the set of everything. |
| 6007 | If you know your father, but don't recognise your father veiled, you know and don't know the same person [Eubulides, by Dancy,R] |
| Full Idea: The 'undetected' or 'veiled' paradox of Eubulides says: if you know your father, and don't know the veiled person before you, but that person is your father, you both know and don't know the same person. | |
| From: report of Eubulides (fragments/reports [c.390 BCE]) by R.M. Dancy - Megarian School | |
| A reaction: Essentially an uninteresting equivocation on two senses of "know", but this paradox comes into its own when we try to give an account of how linguistic reference works. Frege's distinction of sense and reference tried to sort it out (Idea 4976). |
| 6006 | If you say truly that you are lying, you are lying [Eubulides, by Dancy,R] |
| Full Idea: The liar paradox of Eubulides says 'if you state that you are lying, and state the truth, then you are lying'. | |
| From: report of Eubulides (fragments/reports [c.390 BCE]) by R.M. Dancy - Megarian School | |
| A reaction: (also Cic. Acad. 2.95) Don't say it, then. These kind of paradoxes of self-reference eventually lead to Russell's 'barber' paradox and his Theory of Types. |
| 6008 | Removing one grain doesn't destroy a heap, so a heap can't be destroyed [Eubulides, by Dancy,R] |
| Full Idea: The 'sorites' paradox of Eubulides says: if you take one grain of sand from a heap (soros), what is left is still a heap; so no matter how many grains of sand you take one by one, the result is always a heap. | |
| From: report of Eubulides (fragments/reports [c.390 BCE]) by R.M. Dancy - Megarian School | |
| A reaction: (also Cic. Acad. 2.49) This is a very nice paradox, which goes to the heart of our bewilderment when we try to fully understand reality. It homes in on problems of identity, as best exemplified in the Ship of Theseus (Ideas 1212 + 1213). |
| 10661 | 'Composition is identity' says multitudes are the reality, loosely composing single things [Varzi] |
| Full Idea: The thesis known as 'composition is identity' is that identity is mereological composition; a fusion is just the parts counted loosely, but it is strictly a multitude and loosely a single thing. | |
| From: Achille Varzi (Mereology [2003], 4.3) | |
| A reaction: [He cites D.Baxter 1988, in Mind] It is not clear, from this simple statement, what the difference is between multitudes that are parts of a thing, and multitudes that are not. A heavy weight seems to hang on the notion of 'composed of'. |
| 10647 | Parts may or may not be attached, demarcated, arbitrary, material, extended, spatial or temporal [Varzi] |
| Full Idea: The word 'part' can used whether it is attached, or arbitrarily demarcated, or gerrymandered, or immaterial, or unextended, or spatial, or temporal. | |
| From: Achille Varzi (Mereology [2003], 1) |
| 10651 | If 'part' is reflexive, then identity is a limit case of parthood [Varzi] |
| Full Idea: Taking reflexivity as constitutive of the meaning of 'part' amounts to regarding identity as a limit case of parthood. | |
| From: Achille Varzi (Mereology [2003], 2.1) | |
| A reaction: A nice thought, but it is horribly 'philosophical', and a long way from ordinary usage and common sense (which is, I'm sorry to say, a BAD thing). |
| 10649 | 'Part' stands for a reflexive, antisymmetric and transitive relation [Varzi] |
| Full Idea: It seems obvious that 'part' stands for a partial ordering, a reflexive ('everything is part of itself'), antisymmetic ('two things cannot be part of each other'), and transitive (a part of a part of a thing is part of that thing) relation. | |
| From: Achille Varzi (Mereology [2003], 2.1) | |
| A reaction: I'm never clear why the reflexive bit of the relation should be taken as 'obvious', since it seems to defy normal usage and common sense. It would be absurd to say 'I'll give you part of the cake' and hand you the whole of it. See Idea 10651. |
| 10654 | The parthood relation will help to define at least seven basic predicates [Varzi] |
| Full Idea: With a basic parthood relation, we can formally define various mereological predicates, such as overlap, underlap, proper part, over-crossing, under-crossing, proper overlap, and proper underlap. | |
| From: Achille Varzi (Mereology [2003], 2.2) | |
| A reaction: [Varzi offers some diagrams, but they need interpretation] |
| 10658 | Sameness of parts won't guarantee identity if their arrangement matters [Varzi] |
| Full Idea: We might say that sameness of parts is not sufficient for identity, as some entities may differ exclusively with respect to the arrangement of the parts, as when we compare 'John loves Mary' with 'Mary loves John'. | |
| From: Achille Varzi (Mereology [2003], 3.2) | |
| A reaction: Presumably wide dispersal should also prevent parts from fixing wholes, but there is so much vagueness here that it is tempting to go for unrestricted composition, and then work back to the common sense position. |
| 14021 | Worm Perdurantism has a fusion of all the parts; Stage Perdurantism has one part at a time [Crisp,TM] |
| Full Idea: Worm-theoretic Perdurantism says spatio-temporal continuants are mereological fusions of instantaneous temporal parts or stages located at different times; Stage-theoretic Perdurantism says they are instantaneous temporal stages of continuants. | |
| From: Thomas M. Crisp (Presentism [2003], 2.1) | |
| A reaction: [Armstrong, Lewis and Quine defend the first; Sider the second] The Stage view seems to be the common sense view. Sider suggests that the earlier stages are counterparts, not the thing as it currently is. |
| 10652 | Conceivability may indicate possibility, but literary fantasy does not [Varzi] |
| Full Idea: Conceivability may well be a guide to possibility, but literary fantasy is by itself no evidence of conceivability. | |
| From: Achille Varzi (Mereology [2003], 2.1) | |
| A reaction: Very nice. People who cite 'conceivability' in this context often have a disgracefully loose usage for the word. Really, really conceivable is probably our only guide to possibility. |
| 14020 | 'Eternalism' is the thesis that reality includes past, present and future entities [Crisp,TM] |
| Full Idea: I use the term Eternalism for the thesis that reality includes past, present and future entities. (It is sometimes used for the view that all propositions have their truth-value eternally - it is always true or never true). | |
| From: Thomas M. Crisp (Presentism [2003], Intro n.1) | |
| A reaction: 'Eternalism' strikes me as an excellent word for the former meaning, so I shall promote that, and quietly forget the second one. The idea that the future exists has always stuck in my craw, and the belief that Napoleon still exists strikes me as a weird. |
| 14026 | Presentists can talk of 'times', with no more commitment than modalists have to possible worlds [Crisp,TM] |
| Full Idea: We can talk of 'moments of time' as abstract objects. This will be attractive to the presentist. As possible worlds give an economical theory of modal talk, so 'times' gives us a theory for temporal talk. | |
| From: Thomas M. Crisp (Presentism [2003], 3.4) | |
| A reaction: Thus we can utilise 'times', while having no more commitment to them than to possible worlds. Nice. He cites Prior and Fine 1977 and Chisholm 1979. |
| 14022 | The only three theories are Presentism, Dynamic (A-series) Eternalism and Static (B-series) Eternalism [Crisp,TM] |
| Full Idea: Three theories exhaust the options on time: presentism, dynamic eternalism (eternalism with the tensed dynamic A-series view of time, and the totality of events changing over time), and static eternalism (eternalism with the B-series). | |
| From: Thomas M. Crisp (Presentism [2003], 2.4) | |
| A reaction: I think the idea that reality is Static Eternalism is just a misunderstanding, arising from our imaginative ability to take a lofty objective overview of a very fluid reality. The other two are the serious candidates. Present, or Growing-block. |