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Single Idea 12820

[filed under theme 9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects ]

Full Idea

If we reject extensionality in mereology, it has as a consequence that more than one object may have exactly the same parts at the same time, and hence occupy the same position.

Clarification

'Extensionality' says 'same parts - same thing'

Gist of Idea

Without extensional mereology two objects can occupy the same position

Source

Peter Simons (Parts [1987], Intro)

Book Ref

Simons,Peter: 'Parts: a Study in Ontology' [OUP 1987], p.3

A Reaction

Simons defends this claim. I'm unconvinced that we must choose between the two views. The same parts should ensure the same physical essence, which seems to guarantee the same identity. Not any old parts generate an essence.

The 76 ideas from Peter Simons

8973 Einstein's relativity brought events into ontology, as the terms of a simultaneity relationships [Simons]
8979 Slow and continuous events (like balding or tree-growth) are called 'processes', not 'events' [Simons]
8981 Maybe processes behave like stuff-nouns, and events like count-nouns [Simons]
18883 Any equivalence relation among similar things allows the creation of an abstractum [Simons]
18884 Abstraction is usually seen as producing universals and numbers, but it can do more [Simons]
18431 Internal relations combine some tropes into a nucleus, which bears the non-essential tropes [Simons, by Edwards]
12820 Without extensional mereology two objects can occupy the same position [Simons]
12814 Classical mereology says there are 'sums', for whose existence there is no other evidence [Simons]
12817 'Mereological extensionality' says objects with the same parts are identical [Simons]
12819 A 'part' has different meanings for individuals, classes, and masses [Simons]
12815 Classical mereology doesn't apply well to the objects around us [Simons]
12813 Two standard formalisations of part-whole theory are the Calculus of Individuals, and Mereology [Simons]
12816 Classical mereology doesn't handle temporal or modal notions very well [Simons]
12822 Proper or improper part: x < y, 'x is (a) part of y' [Simons]
12823 Overlap: two parts overlap iff they have a part in common, expressed as 'x o y' [Simons]
12824 Disjoint: two individuals are disjoint iff they do not overlap, written 'x | y' [Simons]
12825 Product: the product of two individuals is the sum of all of their overlaps, written 'x · y' [Simons]
12826 Sum: the sum of individuals is what is overlapped if either of them are, written 'x + y' [Simons]
12827 Difference: the difference of individuals is the remainder of an overlap, written 'x - y' [Simons]
12828 General sum: the sum of objects satisfying some predicate, written σx(Fx) [Simons]
12829 General product: the nucleus of all objects satisfying a predicate, written πx(Fx) [Simons]
12830 Universe: the mereological sum of all objects whatever, written 'U' [Simons]
12821 The part-relation is transitive and asymmetric (and thus irreflexive) [Simons]
12832 Complement: the rest of the Universe apart from some individual, written x-bar [Simons]
12831 Atom: an individual with no proper parts, written 'At x' [Simons]
12833 If there are c atoms, this gives 2^c - 1 individuals, so there can't be just 2 or 12 individuals [Simons]
12834 Criticisms of mereology: parts? transitivity? sums? identity? four-dimensional? [Simons]
12835 Does Tibbles remain the same cat when it loses its tail? [Simons]
12837 Four dimensional-objects are stranger than most people think [Simons]
12839 Relativity has an ontology of things and events, not on space-time diagrams [Simons]
12838 Four-dimensional ontology has no change, since that needs an object, and time to pass [Simons]
12836 Fans of process ontology cheat, since river-stages refer to 'rivers' [Simons]
12842 There are real relational changes, as well as bogus 'Cambridge changes' [Simons]
12840 I do not think there is a general identity condition for events [Simons]
12841 I don't believe in processes [Simons]
12844 Dissective: stuff is dissective if parts of the stuff are always the stuff [Simons]
12843 With activities if you are doing it you've done it, with performances you must finish to have done it [Simons]
12845 Some natural languages don't distinguish between singular and plural [Simons]
12846 A 'group' is a collection with a condition which constitutes their being united [Simons]
18847 Each wheel is part of a car, but the four wheels are not a further part [Simons]
12847 Mass nouns admit 'much' and 'a little', and resist 'many' and 'few'. [Simons]
12848 The same members may form two groups [Simons]
12850 To individuate something we must pick it out, but also know its limits of variation [Simons]
12849 Sums are more plausible for pluralities and masses than they are for individuals [Simons]
12854 An entrepreneur and a museum curator would each be happy with their ship at the end [Simons]
12855 The 'best candidate' theories mistakenly assume there is one answer to 'Which is the real ship?' [Simons]
12856 Intermittent objects would be respectable if they occurred in nature, as well as in artefacts [Simons]
12857 Tibbles isn't Tib-plus-tail, because Tibbles can survive its loss, but the sum can't [Simons]
12858 Mixtures disappear if nearly all of the mixture is one ingredient [Simons]
12859 A mixture can have different qualities from its ingredients. [Simons]
12860 Sortal nouns for continuants tell you their continuance- and cessation-conditions [Simons]
12862 Gold is not its atoms, because the atoms must be all gold, but gold contains neutrons [Simons]
12863 Mass terms (unlike plurals) are used with indifference to whether they can exist in units [Simons]
12861 'The wolves' are the matter of 'the pack'; the latter is a group, with different identity conditions [Simons]
12865 Analytic philosophers may prefer formal systems because natural language is such mess [Simons]
12864 We say 'b is part of a', 'b is a part of a', 'b are a part of a', or 'b are parts of a'. [Simons]
12866 Composition is asymmetric and transitive [Simons]
12867 A hand constitutes a fist (when clenched), but a fist is not composed of an augmented hand [Simons]
12871 Objects have their essential properties because of the kind of objects they are [Simons]
12870 We must distinguish the de dicto 'must' of propositions from the de re 'must' of essence [Simons]
12872 The zygote is an essential initial part, for a sexually reproduced organism [Simons]
12873 Original parts are the best candidates for being essential to artefacts [Simons]
12874 An essential part of an essential part is an essential part of the whole [Simons]
12875 One false note doesn't make it a performance of a different work [Simons]
12877 Sums of things in different categories are found within philosophy. [Simons]
12876 Philosophy is stuck on the Fregean view that an individual is anything with a proper name [Simons]
12880 Moments are things like smiles or skids, which are founded on other things [Simons]
12879 Independent objects can exist apart, and maybe even entirely alone [Simons]
12883 Moving disturbances are are moments which continuously change their basis [Simons]
12882 A wave is maintained by a process, but it isn't a process [Simons]
12881 A smiling is an event with causes, but the smile is a continuant without causes [Simons]
12886 A whole requires some unique relation which binds together all of the parts [Simons]
12885 Objects like chess games, with gaps in them, are thereby less unified [Simons]
12889 The limits of change for an individual depend on the kind of individual [Simons]
12888 The wholeness of a melody seems conventional, but of an explosion it seems natural [Simons]
15390 Metaphysics attempts to give an account of everything, in terms of categories and principles [Simons]