Black - against quidditism.pdf - Ted Sider

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Downloaded By: [New York University] At: 21:44 25 May 2010 94 Against Quidditism of 'out'!), it seems sensible to ask what could constitute the identity of other-Humphrey with our Humphrey, and it seems clear that this question can have no answer. Indeed if we extrapolate the everyday view that two spatially separated individuals must be indeed two rather than one, then afortiori it seems that an individual cannot be identical with something separated from it in logical space. Lewis, however, makes no use of this argument (though I can't help suspecting that it motivates his anti-haecceitism). He makes no use of it because he is aware that the haecceitist can concede that nothing constitutes transworld identity but still accept such identity as primitive--just as Lewis himself does with the transworld identity of qualities. He is thus forced to rely on the (far from knock-down) argument that the haecceitist has to turn accidental intrinsic properties into relations; Humphrey can't just be five-fingered; be has to be five-fingered-in-this-world and six-fingered-in-that-world. Now nothing like this pattern of argument against haecceitism will work against quidditism. For a start, it is clear that the same quality can be instantiated at spatially separated locations, so there is nothing immediately problematic about its being located at logically separated worlds. And since on Lewis's view a fundamental quality never has anything intrinsic about it apart from its identity with itself, there can be no argument from accidental intrinsics. The antiquidditist modal realist must, it seems, just rely on the intuition that although in a stipulated possible world what properties are to be found there comes with the stipulation, for real possible worlds something must constitute the identity of properties across logical space. And that is, of course, just what the quidditist denies. The quidditist is, however, committed to what I shall argue is an implausible plethora of distinct possible worlds. Firstly, he is committed to distinctions which my intuitions tell me are distinctions without differences. And secondly, as we shall see, he is going to have serious difficulties with the cardinality of the collection of all possible worlds. Let us start by considering the world isomorphic with ours, but where a quark colour has swapped places with a quark flavour) ° To the inhabitants of such a world, their world looks just like ours, but in reality it is supposed to be quite different. Can that really be? My intuition is that to play the nomological role of some colour or flavour is to be that colour or flavour, and that the idea of two qualities swapping nomological roles is thus unintelligible. This is not a verificationist argument. It is not like the case of a world which is just like ours except for having come into existence five minutes ago complete with fossils and (pseudo-)memories. In such a case there is something distinguishing that world from ours which its inhabitants are prevented from knowing, giving them the illusion that their world is like ours. But in the case of colour/flavour exchange, the inhabitants could happily know all the truths about their world, and the nan'ow content of their knowledge would be identical with ours (or with what ours would be if we knew everything), and still their world is supposed to be different from ours, and their knowledge to differ from ours in its broad content. More apt than the comparison with a world without a past would perhaps be the following: someone living in a Newtonian world with absolute space might be tempted to think that things could all have been ten centimetres to the left of where they are. My intuition is that that would be a mistake, and interestingly, in this case Lewis l0 I shall argue below that this example is physically awry, but nothing hangs on that here.
Downloaded By: [New York University] At: 21:44 25 May 2010 Robert Black 95 would agree, since the supposed alternative possibility only makes sense on the assumption of haecceitism about spatial points. Analogously, the supposed possibility of colour/flavour exchange only makes sense on the assumption of quidditism about fundamental qualities. And parallel intuitions about sensible physics seem to put haecceitism and quidditism in the same boat. It is easy to generate further similar examples. An alien quality is one which happens not to be instantiated in our world. Consider a world isomorphic to ours in its pattern of instantiation of fundamental qualities and relations, but where every fundamental quality or relation has been replaced by an alien one. In that world pseudo-spatiotemporal relations make up a pseudo-space and pseudo-time isomorphic to our space and time, in (or rather pseudo-in) which are found particles with pseudo-mass, pseudo-charge, pseudo-charm and so on. Again, the world looks to its inhabitants just like our world does to us, but it is supposed to be wholly different. If we just consider the possible permutations of monadic qualities, both this-worldly and alien, if there are ~: qualities all together, 2 of which are instantiated in our world, then the total number of such possibilities is 2! (,~) if t0 is finite, and x a otherwise, and according to the quidditist, each is genuinely different from all the others. Or consider a world which is like ours except that wherever some particular quality Q is instantiated in our world, one of two qualities Qa and Q2 is instantiated in it, the choice of which being random and without rhyme or reason. Q1 and Q2 are thus really distinct, though indistinguishable to the inhabitants of that world, since wholly coinciding in nomological role. And the laws of that world are wrongly thought by its inhabitants to be the laws of our world, whereas the correct laws are those which arise from substituting 'Q~x v Qzx' for 'Qx' throughout. H (Or perhaps we do already live in such a world; there are some obvious sceptical arguments hanging around here which I shall not pause to consider.) We might try going further down this road, allowing a single quality to be replaced by infinitely many causally indistinguishable alternatives, or allowing replacement of more than one quality, but there has to be a limit to this process, since by II Although my intuition is that this is not a genuinely alternative possibility, I wouldn't mind admitting it ifI have to, for while it is incompatible with the view that the intramundane identity of a fundamental quality is determined by its nomologieal role, it does not give us a world structurally isomorphic with ours but ineffably different (as does the colour/flavour exchange). Denis Robinson [20] and David Armstrong [1] have used rather similar examples (in Robinson's case, two properties differing not at all in their nomic relations to others, but only in their nomic relations to each other, in Armstrong's case, a total system of nomic properties invariant under some non-trivial pelTnutation) to argue that identity of properties cannot consist in nomic role. Both authors express reservations about their own argument, but Robinson concludes that 'Though I dislike haecceitism, for properties ~ fear it might be the right thing' and Armstrong argues that the solution is to appeal to a different quidditas in the two properties. But suppose that the argument does work: the conclusion to which it leads concerns only the intramundane identity of properties. Take Robinson'sfand g: particles acquire these properties in well-defined circumstances, with a 50% chance of getting either, and if two particles both have f or both have g they repel each other, whereas if they have one of each they attract each other. If we consider the total system of laws in Ramseyfied form with an existential quantifier for each property, f and g have the same nomic profile while being distinct properties. Now perhaps one could avoid this conclusion by insisting on some sort of relational analysis, but suppose we accept it. The conclusion is still not quidditism in my sense, for it does not follow that we can conceive of a possible world distinct from ours wheref and g have swapped roles.
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