Friday, January 14, 2011

Some Questions About Rasmussen's Third Premise

DRAFT: DO NOT COPY OR CITE WITHOUT PERMISSION FROM THE AUTHOR. COMMENTS WELCOME!

We recently noted Joshua Rasmussen's interesting new paper in AJP[1], in which he offers a novel variation on the Leibnizian cosmological argument for a necessary being. Recall that his argument runs as follows:

(1) Normally, for any intrinsic property p that (i) can begin to be
exemplified and (ii) can be exemplified by something that has a cause,
there can be a cause of p’s beginning to be exemplified.
(2) The property c of being a contingent concrete particular is an intrinsic
property.
(3) Property c can begin to be exemplified.
(4) Property c can be exemplified by something that has a cause.
Therefore,
(5) There can be a cause of c’s beginning to be exemplified (1–4).
(6) If (5), then there is a necessary being.
Therefore,
(7) There is a necessary being.

I have three main concerns about the justification for premise (3). First, it appears that Rasmussen's basis for (3) is that one can imagine all concrete particulars having a beginning of existence[2], where imaginability is then taken as at least prima facie justification of metaphysical possibility. However, even if we grant this, one might worry that the justification-conferring ability of such imaginings does not extend to states of affairs as remote from ordinary experience as the beginning of all concrete particulars, any more than it does to the modal premises in (for example) the modal ontological argument and conceivability arguments for dualism.

One might object that the criticism relies on an arbitrarily selective form of modal skepticism, on the grounds that the demand for justification for exotic possibility claims should then apply to the humdrum possibility claims as well. And since we accept the latter without argument, we should, to be consistent, accept the former. But this objection is unpersuasive. For a number of plausible proposals of our knowledge of humdrum metaphysical possibilities have been proposed. For example, it has been proposed that such knowledge is grounded in (i) our facility with counterfactual reasoning in ordinary contexts[3], (ii) our folk theory of how the world works [4], and (iii) arguments from analogy/relevant similarity with the actual world [5]. Such accounts can nicely explain the epistemic force of relatively uncontroversial thought experiments involving humdrum metaphysical possibilities (e.g., the Gettier cases), while leaving the more "far out" or "exotic" modal claims (e.g., that an Anselmian Being is possible, that our minds can exist apart from matter, etc.) unjustified.

But suppose this is wrong, and that imaginability is indeed sufficient prima facie evidence of metaphysical possibility in this case. This brings me to my second criticism of premise (3). For even if that's right, it's not clear that it would follow that all concrete particulars are contingent in the requisite sense. For it's at least epistemically possible that at least some such particulars are metaphysically contingent and yet factually necessary. That is, it’s at least epistemically possible that while there are metaphysically possible worlds at which they do not exist, they are eternal, metaphysically independent, "free standing" beings at all the worlds in which they do exist. And if that's right, then even if our ability to imagine them failing to exist provides us with sufficient evidence that they do not exist in some metaphysically possible worlds, it would not provide sufficient evidence that they began to exist.

But perhaps Rasmussen need not appeal to armchair considerations of modal epistemology and thought experiments to justify premise (3). For he might say that we can appeal to scientific confirmation of the beginning of all concrete particulars in the singularity described in standard models of the Big Bang theory of the origin of our universe. This is at least hinted at in his assertion that, "...we can imagine a beginning to the existence of contingent bits of matter as they explode out of an initial singularity" [6]. This brings me to my third and final criticism of premise (3), for unless one is an expert in the relevant scientific fields, one will likely not be competent to evaluate the evidence for this claim on one’s own. I take it that that applies to most of us. We must therefore defer to the relevant experts. But the problem is that there is significant divergence of opinion among the experts on this issue, as there is no consensus among them that our universe had an absolute beginning in a singularity[7]

One might reply that my last two criticisms miss the point. For Rasmussen’s argument doesn't assume that all concrete particulars in fact began to exist, but rather that they can begin to exist. But the problem is that such a reply requires the denial of the widely shared intuition that things have their origins of metaphysical necessity. To see this, suppose origin essentialism is true (i.e., things have their origins of metaphysical necessity), and suppose we give our universe a Kripkean baptism: We say (pointing to the universe), "Let that be called 'Uni'. 'Uni' is now a Kripkean rigid designator, and thus refers only to our universe in all the possible worlds in which it exists.

Holding our universe fixed via the term ‘Uni’, we can start considering modal claims about it. There are two relevant possibilities for us to consider in this regard: (i) Uni has its origin in the causal activity of a necessary being, and (ii) Uni has no origin. Now if (i) is true, then by origin essentialism, this is an essential property of Uni, in which case there is no possible world in which Uni lacks such an origin. On the other hand, if (ii) is true, then Uni lacks an origin in the causal activity of a necessary being, and so this fact about Uni is essential to it, in which case there is no possible world in which it has an origin in the causal activity of a necessary being.

The moral, then, is that if we accept origin essentialism like good Kripkeans, then we will think that facts about whether our universe has an explanation in terms of a necessary being don't vary from world to world. But if so, then we can't know whether our universe could have a beginning unless we know beforehand that it in fact had a beginning.[8]

In conclusion, I have argued that Rasmussen’s new case for a necessary being is unsuccessful. The main reason is that it relies on a modal premise that lacks sufficient justification from both armchair and scientific sources. Unless Rasmussen can offer such justification, the argument will remain unpersuasive.

Endnotes
[1] Rasmussen [2010: 1-6].
[2] Rasmussen [2010: 4].
[3] Williamson [2007].
[4] Williamson [2007]; Hanrahan [2007: 125-146].
[5] Hawke [forthcoming].
[6] Rasmussen [2010: 4].
[7] There are several alternative models to the standard Big Bang model that don't involve the origin of the universe in a singularity, but here's one. According to M-theory (the theory that unifies the five versions of superstring theory), there are entities called 'branes', or multi-dimensional membranes (ranging from 0 (for point-particles) to 10 dimensions, and our universe is just one 4-dimensional brane among many branes existing within a larger 11-dimensional space-time. Thus, according to M-theory, the beginning of our universe is not the absolute beginning of concrete particulars, and the realm of concrete particulars may well have no beginning. On M-theory, then, the need for an absolute temporal beginning of concrete particulars doesn't arise. For a popular account of M-theory, see, e.g., Greene [2003].
[8]One could of course reject origin essentialism, or restrict its scope in a way favorable to the argument, but then the worry is that the audience for the argument will shrink considerably.


References
Greene, Brian 2003. The Elegant Universe, New York: Norton & Norton Company, Inc.
Hanrahan, Rebecca 2007. "Imagination and Possibility", The Philosophical Forum 38/2: 125-146.
Hawke, Peter forthcoming. "Van Inwagen's Modal Skepticism", Philosophical Studies (forthcoming).
Rasmussen, Joshua 2010. “A New Argument for a Necessary Being”, Australasian Journal of Philosophy 88/3: 1-6.
Williamson, Timothy 2008. The Philosophy of Philosophy, Oxford, UK: Oxford University Press.

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