A Principle of Transworld Volition

Lately I've been working on a theory of mereology (the metaphysics of parts and wholes). The gist of the thesis is this: Some aggregate of matter M constitutes a genuine mereological sum iff M is an artifact. I won't get into the nuances here (although I will be in upcoming entries), but I wanted to propose a principle which a part (no pun intended) of my theory hinges on. The principle is what I call the "Principle of Transworld Volition". What it amounts to is the following claim:

PTV=def The thesis that some choice C made in some world W1 is a transworld volition iff C would also have been made in some near-identical world W2.

Here a "near-identical" world is one which is identical in all important, or relevant, ways to another, but different in some trivial way (or set of trivial ways). So, for example, take W to be the actual world, and take W* to be a near-identical world which differs from our own only in the following trivial way: There exists in W* a tiger who was born (by some genetic mishap) with three heads. This fact, as you can see, would seem to have no significant bearing on any other facts about W and W* being significantly different. Thus it is, as we say, trivial. I think several interesting things may follow from an application of such a principle, but I'll limit myself here to how I apply it in my theory.

Let's say some person (call him 'Smith') finds himself wanting to build a chair. Further, let's assume that Smith doesn't know what the basic constituents of the universe he finds himself in are (e.g., if he finds himself in our universe, he doesn't know that the universe is essentially composed of quarks). Now let's assume that Smith's counterpart, call him Smith2, finds himself in another world near-identical to Smith's, with only the following difference: In Smith's world, the universe is composed of quarks, in Smith2's world, the universe is composed of duarks. Exactly how quarks and duarks differ can be left up to the imagination (perhaps in Smith2's world, duarks compose quarks, or whatever). Now, being near-identical to Smith's world, Smith2 also finds himself wanting to build a chair. Futher, they both end up making the decision to build the chair. In addition, Smith2 also doesn't know what his universe is composed of. So, for all practical purposes, Smith doesn't know whether he's in quark-world or duark-world (and hence whether he's Smith or Smith2!). Now, if they both decide to build the chair at t1, and both have the same epistemic status at t1, then it seems that the fact that the universe is composed of quarks or duarks is irrelevant to the chair's actualization in either world. Hence, the more fundamental fact about the chair in both worlds is that it is a chair, not an aggregate of quarks arranged chairwise, or an aggregate of duarks arranged chairwise. It follows (with several other assumptions I'll get into later), that we have a genuine mereological sum (assuming it's the fact that part-facts supervene on whole-facts that make some aggregate a true whole).

And so it seems that, if we have a case of transworld volition on our hands, then we have a plausible instance of a mereological sum having been produced by that volition (assuming, of course, that the volition was artifact-directed). The reason is that, as expressed before, if the fact that the whole is made of such and such parts is trivial to the whole's being brought into existence, then it would seem that the fact that it is a whole is more fundamental than the fact that it's made of this or that group of parts.