| 15845 | It seems absurd that seeing a person's limbs, the one is many, and yet the many are one [Plato] |
| Full Idea: Someone first distinguishes a person's limbs and parts and asks your agreement that all the parts are identical with that unity, then ridicules you that you have to admit one is many, and indefinitely many, and again that the many are only only one thing. | |
| From: Plato (Philebus [c.353 BCE], 14e) | |
| A reaction: This is a passing aporia, but actually seems to approach the central mystery of the metaphysics of identity. A thing can't be a 'unity' if there are not things to unify? So what sorts of 'unification' are there? |
| 13270 | Are a part and whole one or many? Either way, what is the cause? [Aristotle] |
| Full Idea: There is a difficulty about part and whole, ...whether the part and the whole are one or more than one, and in what way they can be one or many, and, if they are more than one, in what way they are more than one. | |
| From: Aristotle (Physics [c.337 BCE], 185b11), quoted by Kathrin Koslicki - The Structure of Objects 6.3 | |
| A reaction: He only states the problem here, but doesn't pursue it. I take the real question of mereology to be what makes a many into a one. I don't see a problem with a many being simultaneously a one. |
| 13282 | Aristotle relativises the notion of wholeness to different measures [Aristotle, by Koslicki] |
| Full Idea: Aristotle proposes to relativise unity and plurality, so that a single object can be both one (indivisible) and many (divisible) simultaneously, without contradiction, relative to different measures. Wholeness has degrees, with the strength of the unity. | |
| From: report of Aristotle (works [c.330 BCE]) by Kathrin Koslicki - The Structure of Objects 7.2.12 | |
| A reaction: [see Koslicki's account of Aristotle for details] As always, the Aristotelian approach looks by far the most promising. Simplistic mechanical accounts of how parts make wholes aren't going to work. We must include the conventional and conceptual bit. |
| 10397 | Abelard's mereology involves privileged and natural divisions, and principal parts [Abelard, by King,P] |
| Full Idea: Abelard's theory of substantial integral wholes is not a pure mereology in the modern sense, since he holds that there are privileged divisions; ..the division of a whole must be into its principal parts. Some wholes have a natural division. | |
| From: report of Peter Abelard (works [1135]) by Peter King - Peter Abelard 2 | |
| A reaction: This is a mereology that cuts nature at the joints, rather than Lewis's 'unrestricted composition', so I find Abelard rather appealing. |
| 10706 | Dedekind originally thought more in terms of mereology than of sets [Dedekind, by Potter] |
| Full Idea: Dedekind plainly had fusions, not collections, in mind when he avoided the empty set and used the same symbol for membership and inclusion - two tell-tale signs of a mereological conception. | |
| From: report of Richard Dedekind (Nature and Meaning of Numbers [1888], 2-3) by Michael Potter - Set Theory and Its Philosophy 02.1 | |
| A reaction: Potter suggests that mathematicians were torn between mereology and sets, and eventually opted whole-heartedly for sets. Maybe this is only because set theory was axiomatised by Zermelo some years before Lezniewski got to mereology. |
| 14121 | The part-whole relation is ultimate and indefinable [Russell] |
| Full Idea: The relation of whole and part is, it would seem, an indefinable and ultimate relation, or rather several relations, often confounded, of which one at least is indefinable. | |
| From: Bertrand Russell (The Principles of Mathematics [1903], §135) | |
| A reaction: This is before anyone had produced a mathematical account of mereology (qv). |
| 10657 | The counties of Utah, and the state, and its acres, are in no way different [Goodman] |
| Full Idea: A class (counties of Utah) is different neither from the individual (state of Utah) that contains its members, nor from any other class (acres of Utah) whose members exhaust the whole. For nominalists, distinction of entity means distinction of content. | |
| From: Nelson Goodman (The Structure of Appearance [1951], p.26), quoted by Achille Varzi - Mereology 3.1 | |
| A reaction: This is a nice credo for the nominalist version of mereology. You can still have a mereology that commits you to the wholes as well as the parts. Cf. Lewis in Idea 10660. |
| 10806 | Megethology is the result of adding plural quantification to mereology [Lewis] |
| Full Idea: Megethology is the result of adding plural quantification, as advocated by George Boolos, to the language of mereology. | |
| From: David Lewis (Mathematics is Megethology [1993], p.03) |
| 10662 | Mereology is 'nihilistic' (just atoms) or 'universal' (no restrictions on what is 'whole') [Inwagen, by Varzi] |
| Full Idea: Van Ingwagen writes of 'mereological nihilism' (that only mereological atoms exist) and of 'mereological universalism' (adhering to the principle of Unrestricted Composition). | |
| From: report of Peter van Inwagen (Material Beings [1990], p.72-) by Achille Varzi - Mereology 4.3 | |
| A reaction: They both look mereologically nihilistic to me, in comparison with an account that builds on 'natural' wholes and their parts. You can only be 'unrestricted' if you view the 'wholes' in your vast ontology as pretty meaningless (as Lewis does, Idea 10660). |
| 13331 | Part and whole contribute asymmetrically to one another, so must differ [Fine,K] |
| Full Idea: The whole identity of a part is relevant to whether it is a part, but the identity of the whole makes a part a part. The whole part belongs to the whole as a part. The standard account in terms of time-slices fails to respect this part/whole asymmetry. | |
| From: Kit Fine (Things and Their Parts [1999], §2) | |
| A reaction: Hard to follow, but I think the asymmetry is that the wholeness of the part contributes to the wholeness of the whole, while the wholeness of the whole contributes to the parthood of the part. Wholeness does different jobs in different directions. OK? |
| 9928 | Mereology implies that acceptance of entities entails acceptance of conglomerates [Burgess/Rosen] |
| Full Idea: Mereology has ontological implications. The acceptance of some initial entities involves the acceptance of many further entities, arbitrary wholes having the entities as parts. It must accept conglomerates. Geometric points imply geometric regions. | |
| From: JP Burgess / G Rosen (A Subject with No Object [1997], II.C.1.b) | |
| A reaction: Presumably without the wholes being entailed by the parts, there is no subject called 'mereology'. But if the conglomeration is unrestricted, there is not much left to be said. 'Restricted' composition (by nature?) sounds a nice line. |
| 15004 | 'Gunk' is an object in which proper parts all endlessly have further proper parts [Sider] |
| Full Idea: An object is 'gunky' if each of its parts has further proper parts; thus gunk involves infinite descent in the part-whole relation. | |
| From: Theodore Sider (Writing the Book of the World [2011], 07.11.2) |
| 15841 | Mereology began as a nominalist revolt against the commitments of set theory [Harte,V] |
| Full Idea: Historically, the evolution of mereology was associated with the desire to find alternatives to set theory for those with nomimalist qualms about the commitment to abstract objects like sets. | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 1.2) | |
| A reaction: Goodman, for example. It is interesting to note that the hardline nominalist Quine, pal of Goodman, eventually accepted set theory. It is difficult to account for things by merely naming their parts. |
| 8465 | Mereology has been exploited by some nominalists to achieve the effects of set theory [Orenstein] |
| Full Idea: The theory of mereology has had a history of being exploited by nominalists to achieve some of the effects of set theory. | |
| From: Alex Orenstein (W.V. Quine [2002], Ch.3) | |
| A reaction: Some writers refer to mereology as a 'theory', and others as an area of study. This appears to be an interesting line of investigation. Orenstein says Quine and Goodman showed its limitations. |
| 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. |
| 12815 | Classical mereology doesn't apply well to the objects around us [Simons] |
| Full Idea: The most fundamental criticism of classical mereology is that the theory is not applicable to most of the objects around us, and is accordingly of little use as a formal reconstruction of the concepts of part and whole which we actually employ. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: This sounds splendidly dismissive, but one might compare it with possible worlds semantics for modal logic, which most people take with a pinch of salt as an actual commitment, but find wonderfully clarifying in modal reasoning. |
| 12819 | A 'part' has different meanings for individuals, classes, and masses [Simons] |
| Full Idea: It emerges that 'part', like other formal concepts, is not univocal, but has analogous meanings according to whether we talk of individuals, classes, or masses. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: He suggests that unrestricted sums are appropriate for the last two, but not for individuals. There must be something univocal about the word - some awareness of a possible whole or larger entity to which the thing could belong. |
| 12832 | Complement: the rest of the Universe apart from some individual, written x-bar [Simons] |
| Full Idea: The 'complement' of each individual in mereology is the rest of the Universe outside it, that is U - x, but written as x-bar [x with a horizontal bar above it]. | |
| From: Peter Simons (Parts [1987], 1.1.10) | |
| A reaction: [Don't have a font for x-bar] See Idea 12831 for the 'Universe'. Simons suggest that the interest of this term is mainly historical and algebraic. |
| 12834 | Criticisms of mereology: parts? transitivity? sums? identity? four-dimensional? [Simons] |
| Full Idea: Main criticisms of mereology: we don't mean 'part' as improper; transitivity of 'part' is sometimes not transitive; no guarantee that there are 'sums'; the identity criteria for individuals are false; we are forced into materialistic four-dimensionalism. | |
| From: Peter Simons (Parts [1987], 3.2) | |
| A reaction: [Compressed summary; for four-dimensionalism see under 'Identity over Time'] Simons says these are in ascending order of importance. |
| 10707 | Mereology elides the distinction between the cards in a pack and the suits [Potter] |
| Full Idea: Mereology tends to elide the distinction between the cards in a pack and the suits. | |
| From: Michael Potter (Set Theory and Its Philosophy [2004], 02.1) | |
| A reaction: The example is a favourite of Frege's. Potter is giving a reason why mathematicians opted for set theory. I'm not clear, though, why a pack cannot have either 4 parts or 52 parts. Parts can 'fall under a concept' (such as 'legs'). I'm puzzled. |
| 13258 | The 'aggregative' objections says mereology gets existence and location of objects wrong [Koslicki] |
| Full Idea: The 'aggregative' objection to classical extensional mereology is that it assigns simply the wrong, set-like conditions of existence and spatio-temporal location to ordinary material objects. | |
| From: Kathrin Koslicki (The Structure of Objects [2008], 5.1) | |
| A reaction: [She attributes this to Kit Fine] The point is that there is more to a whole than just some parts, otherwise you could scatter the parts across the globe (or even across time) and claim that the object still existed. It's obvious really. |