Macro and Micro Necessity

Macro and Micro Necessity

A curious fact of necessity studies: although necessity is liberally spoken of, its extent is rarely tabulated. We find reference to necessities involving people and items of furniture (and the occasional cat) but little in the way of mapping the full distribution of necessities in the world, or their interconnections. We learn that tables are necessarily made of wood (sometimes), that queens have their actual parents necessarily, that people are necessarily human, that Superman is necessarily identical to Clark Kent, and whatnot. But what about the rest of nature—what necessities does it harbor? What about people parts or molecules or planets or oceans or families or logical connectives? Let’s talk about arms: is it an essential property of a particular human arm that it is an arm? Could an arm have been a tooth or a bladder? I think not: maybe at a pinch an arm could function as a leg, but surely its arm anatomy is essential to it. If you reduce an arm to a pile of dust, it no longer exists; it isn’t a dusty arm. Presumably the same thing is true of other body parts, even descending to the very small. Is a particular molecule essentially a molecule? If you break it apart, does it still exist? Its constituent atoms do, but the molecule itself seems to be dead and gone. An electron is necessarily an electron. A galaxy is necessarily a galaxy: you can’t spread its constituent stars far and wide and still have a galaxy, just the components of an erstwhile galaxy (of course, it could turn out that what you think is a galaxy isn’t really one). A generalization is emerging: everything has some essential property (or properties). A thing’s kind is essential to it, on pain of non-existence. So, necessity is everywhere in the universe, not restricted to certain special objects. The same is obviously true for identity, since everything is necessarily self-identical. What about composition? Abstract objects fail this necessity claim: numbers, properties, and logical connectives are not composed of anything, so are not necessarily composed of what actually composes them. Origin is a challenging case: is it just people and other organisms that have their origin essentially? Well, rocks certainly don’t have their parentage essentially, since they don’t have parents; but there is an analogue of parentage that seems to apply more generally, viz. causal antecedents. Does the earth have its causal origin essentially? Yes, in that a planet caused by different events, with an origin in different celestial materials, would not be the earth—though it might be qualitatively identical to the earth. Ditto stars, galaxies, and even the universe itself (it needs that big bang to be this universe). We can even argue that it is essential to me that I was produced by a universe caused by the actual big bang that occurred—I am logically (metaphysically) tied to that specific origin event. But what about object parts? Does Queen Elizabeth’s right arm necessarily derive from her actual parents? Could it (that arm) exist and not originate from her biological parents, perhaps attaching to someone else? I am inclined to say no: she necessarily has those parents, so her arm does too. But it is not true that allher physical parts must have originated in those particular people: a molecule in her arm could have come from somewhere else; in some possible world that molecule never made it into her arm. It wasn’t caused to exist by her parents (by their gametes) unlike Elizabeth and her arm. Not every part of an animal necessarily originates from the activities of its parents. In every possible world in which Elizabeth’s arm exists Elizabeth’s parents exist, but the same is not true of the molecules that compose her arm. This is an interesting discovery about necessity and parthood: it only goes so far down. And it leads to the following question: what is the relation between macro necessity and micro necessity? Does the former supervene on the latter? If you duplicate the micro necessities, do you get the same macro necessities? If X is necessarily human and is composed of micro entities that have certain properties necessarily, is Y also necessarily human given that it is composed of the same kinds of micro necessities? Are micro-modal duplicates identical macro-modally? That is, does the modal micro-world determine the modal macro-world? Do lots of little necessities fix the big necessities? If they do, necessities can be interconnected at different levels of analysis (different scales). The answer appears to be yes: being human supervenes on molecular composition, so being necessarily human should also thus supervene, given no modal difference at the molecular level. However, a reduction looks infeasible: you can’t reduce being necessarily human to a bunch of molecules being necessarily molecules (or such and such a type of molecules).[1] We have micro-to-macro supervenience but not macro-to-micro reduction. The case is thus analogous to the mental and the physical. Macro modal truths are not (generally) translatable into micro modal truths. Modal metaphysics turns out to have the same general shape, dependence-wise, as mental metaphysics.[2]

[1] Actually, this may not be so obvious given sufficient ingenuity, but I’ll let it stand. A reformulation in terms of sub-molecular particles might be more apodictic.

[2] In this paper I simply assume the apparatus and examples introduced by Kripke in Naming and Necessity. I just take his position a few steps further.  It is notable that he does not try to extend his conclusions into other areas. What about the thesis that conjunction is necessarily truth-functional, or that oceans have their geographical location essentially?

 

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5 replies
  1. Dan D'Agostino
    Dan D'Agostino says:

    Nagarjuna worked this out in his Madhyamakāvatāra about 1,800 years ago. All things have two kinds of identity/truth/reality.They are all empty of inherent existence on the ultimate level, but they can all be said to exist on the relative level to the extent that they are functional and that you don’t claim that they have inherent existence. No phenomenon have an objective reality, but they do exist to the extent that they make sense — that we can work with them. In the end, the most we can say is that all things arise due to causes and conditions and so all things are necessarily interdependent. To their detriment, most Western philosophers simply dismiss Madhyamika philosophy before dismissing it out of hand simply because it originated in India and its not something they’ve been exposed to. Read Jay Garfield’s “Engaging Buddhism” for a scholarly discussion of Nagarjuna’s profound take on the points you raise.

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