I give a critique of the argument against the Identity of Indiscernibles found in Max Black's dialogue "The Identity of Indiscernibles". I begin by postulating and giving existence and individuation conditions for actually existent thought experiment characters on analogy with fictional characters as postulated in Peter van Inwagen's "Creatures of Fiction". I then show that Black's two-spheres thought experiment raises not one but two discernibility questions: 1) Is it true in the two-spheres thought experiment that there exist two indiscernible spheres? (...) NO. 2) Is it true in the actual world that there are two indiscernible sphere-characters? YES. (shrink)

I show that a particular version of Hume's Dictum together with the falsity of Composition as Identity entails an incoherency, so either that version of Hume's Dictum is false or Composition as Identity is true. I conditionally defend the particular version of Hume's Dictum in play, and hence conditionally conclude that Composition as Identity is true. I end by suggesting an alternative way out for a persistent foe of Composition as Identity, namely mereological nihilism.

This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

Hume's Dictum (HD) says, roughly and typically, that there are no metaphysically necessary connections between distinct, intrinsically typed, entities. HD plays an influential role in metaphysical debate, both in constructing theories and in assessing them. One should ask of such an influential thesis: why believe it? Proponents do not accept Hume's arguments for his dictum, nor do they provide their own; however, some have suggested either that HD is analytic or that it is synthetic a priori (that is: motivated by (...) intuitions we have no good reason to question). Here I explore whether belief in HD is directly justified on either grounds. I motivate and present more formal characterizations of HD; I show that there are good prima facie cases to be made for HD's being analytic and for its being synthetic a priori; I argue that each of the prima facie cases fails, some things considered. I close by offering two suggestions for how belief in HD might be indirectly justified on argumentative grounds. (shrink)

I argue that the standard counterexamples to the identity of indiscernibles fail because they involve a commitment to a certain kind of primitive or brute identity that has certain very unpalatable consequences involving the possibility of objects of the same kind completely overlapping and sharing all the same proper parts. The only way to avoid these consequences is to reject brute identity and thus to accept the identity of indiscernibles. I also show how the rejection of the identity of indiscernibles (...) derives some of its support from its affinity with a Kripkean account of trans-world identity and theories of direct reference. (shrink)

I argue for a property mereology and for mereological bundle theory. I then apply this theory to the one over many problem (universals) and puzzles concerning persistence and material constitution.

I discuss puzzles involving coinciding material objects (such as statues and their constitutive lumps of clay) and propose solutions.

The strongest version of the principle of the Identity of Indiscernibles states that of necessity, there are no distinct things with all their universals in common (where such putative haecceities as being Aristotle do not count as universals: I use 'universal' rather than 'property' here and in what follows for the simple reason that 'universal' is the term of art that most safely excludes haecceities from its instances). It is commonly supposed that Max Black's famous paper 'The identity of indiscernibles' (...) (2) refutes this thesis. (Armstong's [1], chapter 9 is representative here.) Black argues ([2], p. 156) that it is perfectly possible that there be a world consisting solely of two indiscernible spheres at some distance to each other and that this world constitutes a counterexample to the principle above. The strongest version of the bundle theory of substance claims that of necessity, the substances that make up the world are bundles of universals.1 It is commonly supposed that a consequence of Black's defeat of the principle of the Identity of Indiscernibles is that this bundle theory of substance is mistaken. (Again, Armstong's [1] is representative.) I shall argue that Black's thought experiment does not defeat the bundle theory and that, as a result, the bundle theory can be used to salvage the principle of the Identity of Indiscernibles. (shrink)

Putative counterexamples to the Principle of Identity of Indiscernibles (PII) are notoriously inconclusive. I establish ground rules for debate in this area, offer a new response to such counterexamples for friends of the PII, but then argue that no response is entirely satisfactory. Finally, I undermine some positive arguments for PII.

1. The Bundle Theory I shall discuss is a theory about the nature of substances or concrete particulars, like apples, chairs, atoms, stars and people. The point of the Bundle Theory is to avoid undesirable entities like substrata that allegedly constitute particulars. The version of the Bundle Theory I shall discuss takes particulars to be entirely constituted by the universals they instantiate.' Thus particulars are said to be just bundles of universals. Together with the claim that it is necessary that (...) particulars have constituents, the fundamental claim of the Bundle Theory is: (BT) Necessarily, for every particular x and every entity y, y constitutes x if and only ify is a universal and x instantiates y. 2 The standard and supposedly devastating objection to the Bundle Theory is that it entails or is committed to a false version of the Principle of Identity of Indiscernibles (Armstrong 1978: 91, Loux 1998: 107), namely: (Pll) Necessarily, for all particulars x and y and every universal z, if z is instantiated by x if and only if z is instantiated byy, then x is numerically identical with y. The most famous counterexample to the Identity of Indiscernibles is that put forward by Max Black, consisting of a world where there are only two iron spheres two miles apart from each other, having the same diameter, temperature, colour, shape, size, etc (Black 1952: 156). Let us from now on think of the properties of the spheres in this world as universals. The possibility of this world, which I shall hereafter refer to as 'Black's world', makes (Pll) false.' And according to common philosophical opinion this means that the Bundle Theory is false.. (shrink)