On Being in the Same Place at the Same Time
Wiggins (David)
Source: Rea - Material Constitution - A Reader
Paper - Abstract

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  1. S is the principle1 that “Two things cannot completely occupy the same place / volume / sub-volume at the same time”.
  2. Apparent exceptions that are fairly easy to explain2 include:-
    • Proper Parts: My forearm only partly3 occupies the volume occupied by my body. The apparent exception “doesn’t count”.
    • Sponges: The point is to “mingle” two things – in this case a sponge and a body of water – and then to recover them both afterwards. The things have to persist, or we can’t say they are two things4 in the same pace at the same time. Wiggins also considers (nomologically counterfactual) mingling as the atomic and subatomic level5. This “doesn’t count” either.
  3. Wiggins thinks he can resolve but one of the “difficult” questions arising from all this, but S is still inadequately formulated.
  4. The “is” of Constitution: Wiggins considers a tree6 (T) and its constituent matter (W). T and W occupy the same place at the same time, but are non-identical – because of Leibniz’s Law and the fact that they have different persistence conditions.
    • W survives T’s decomposition into cellulose molecules, while T does not.
    • T survives the loss of some of the constituent cells of W, in the course of organic change, while W does not.
  5. Wiggins thinks it’d be a “trick” to define an aggregate W1 with persistence7 conditions exactly the same as the tree’s. A trick because all you’ve done is define a tree.
  6. Wiggins spells this out: we have “contrived” an identity between stuff (W) and substance (T) by introducing a concept foreign to things falling under the “stuff” category – namely organisation.
  7. Wiggins has a footnote saying that more can be said about identity and the mereological treatment of aggregates – and refers us to "Wiggins (David) - Identity & Spatio-temporal Continuity", pp. 11-13, 67-8, 728.
  8. Wiggins has an excellent footnote9 illustrating – for artefacts – the difference between the stuff and the artefact from which the stuff is made. He proves, by transitivity, that the artefact cannot be identical to its stuff – in this case sweater, wool and socks – since the sweater is not identical to the socks, neither can be identical to the wool from which – at different times – they were made. The stuff (wool) must pre-exist the fabrication of the artefact, but the artefact cannot pre-exist its fabrication.
  9. However, he goes on to argue that none of this implies that T is something over and above W. His definition of over and above is open to objection10, in that he wants it to mean merely that there are no (material) parts of T that are not in W, or as he says, W fully exhausts11 the matter of T.
  10. Wiggins’s understanding of constitution12 includes:-
    • The “is” of material constitution is not the “is” of identity.
    • “x is constituted of y” is equivalent to:-
      … “x is made of y”, or
      … “x consists of y”, or
      … “x is wholly composed of y”, or
      … “x is merely y”, or
      … “x merely consists of y”.
  11. Wiggins notes that if T = W is a consequence of materialism, then Wiggins is not a materialist13, as he denies this equation.
  12. Wiggins claims that his denial that T=W only puts an uninteresting14 obstacle in the way of reducing botany to organic chemistry.
  13. Wiggins leaves T & W with the remark that what he’s shown is similar to a philosophical commonplace of assigning objects to different logical types. He prefers his approach, however, because it makes a smaller claims (he says) for two reasons:-
    • 1. It allows for a clear statement of the connection between objects and their constituting stuff, and
    • 2. The Leibnizian principle for the predicative “is” (as opposed to the constitutive “is”) is highly intelligible15
      If and only if A is an f (or is phi) then A is identical with an f (or with one of the phi-things); and if and only if A is one of the f's (or phi-things) then it must share all its properties with that f (or phi-thing).
  14. There is more to be said on the topic of “ranges of significance” – we’re referred to Russell’s simple or ramified Theory of Types16.
  15. The lesson from T & W is that we need to reformulate principle S as S*, namely
      S*: No two things of the same kind can occupy the same volume at exactly the same time
  16. Wiggins’s gloss on kind is “… satisfy (the same) sortal or substance concept”.
  17. He thinks there are at least three reasons for thinking this a necessary truth:-
    • 1. Space can be mapped only by its occupants.
    • 2.
    • 3.
  18. "Wiggins (David) & Woods (Michael J.) - Symposium: The Individuation of Things and Places"
  19. Wiggins closes with an application of principle S* to the problem of Tib and Tibbles. He attributes the puzzle to William of Sherwood, via Geach17
  20. … to be completed.


In-Page Footnotes

Footnote 1: It is something of an open question whether S is a physical or metaphysical question. Wiggins subsequently considers counterfactual physical circumstances which would allow indefinitely fine commingling of two distinct things, but this still leaves him thinking there’s a problem to solve. So, he thinks there’s an a priori metaphysical issue at stake.

Footnote 2: What’s the compulsion to believe S? Worries often have to do with language (how would our counting work – or else various epistemological claims; these are Olson’s worries about persons and animals occupying the same place at the same time), but the worries ought to run deeper than this.

Footnote 3: The conundrums of Dion / Theon and Tib / Tibbles are relevant here.

Footnote 4: Is there an issue caused by the supposed possibility of intermittent existence?

Footnote 5: Something like the case of miscible fluids would only take us to the molecular level – but at least that’s further than sponges.

Footnote 6: A change from “the statue and the clay” (See Goliath and Lump1 in "Gibbard (Allan) - Contingent Identity", etc.) – and better, since artefacts might be a special case where human concerns and arbitrariness muddy the waters.

Footnote 7: I’d thought of aggregates having less strict persistence conditions than those demanded by mereological essentialism – a heap that has lost a grain is still the same heap – but Wiggins picks up on this. That said, his “take” is an extreme one for the sake of argument, but you could define persistence conditions for aggregates that didn’t mirror those of organic objects, and that were, therefore, less contrived.

Footnote 8: Footnote 9: Footnote 10: Footnote 11: Footnote 13: I find this paragraph very difficult to construe. I repeat it here for reference:- Footnote 14: What does he mean by this? That the obstacle is illusory?

Footnote 15: This seems to be a restatement of Leibniz’s Law in sortal terms.

Footnote 16: Presumably, this survives Russell’s failure to reduce mathematics to logic. Wiggins gives the following references:- Footnote 17: He thanks Geach for allowing him to use the material, but gives no reference. For some reason, he doesn’t mention the ancient Dion and Theon (Click here for Note), which is of exactly the same form as Tib and Tibbles.

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