Sunday, November 22, 2015

Metaphysically Necessary Beings, Factually Necessary Beings, and Two Kinds of Brute Facts

I've argued for the live epistemic possibility that matter/energy (or, if matter/energy isn't fundamental, the stuff of which matter/energy is ultimately composed) is factually necessary. That is, it's a live epistemic possibility that while there might be possible worlds at which matter/energy does not exist, it's eternal, uncaused, existentially independent, and de facto indestructible at the actual world. I've also argued that factually necessary matter/energy satisfies a weaker version of PSR:
(PSRfn): Every existing thing has an explanation of its existence, either in terms of the factual necessity of its own nature or in terms of an external cause.
Finally, I've attempted to motivate this proposal and answer a number of objections to it on various occasions. Here, however, I'd like to set aside these points and defend PSRfn by means of a tu quoque argument of sorts. Here's a thumbnail sketch of the argument: A number of proponents of the principle of sufficient reason (PSR) have accepted a revised version that allows for brute facts of certain sorts, on the grounds that unrestricted versions of PSR lead to absurdities, or conflict with other things we have reason to accept. And because of this, they reason, such revisions, and the resultant acceptance of certain sorts of brute facts, are acceptable. But (I argue) if such a basis for revising and restricting PSR (and thereby allowing for certain sorts of brute facts) is acceptable, then by the same token, so is the basis for further revising PSR to PSRfn, and, consequently, granting the acceptability of the brute existence of a factually necessary being.

Of course the key move in the argument is following recent proponents of PSR in accepting a distinction between between objectionably vs. unobjectionably brute facts. Here's a quick sketch and illustration of the distinction:

1. Objectionable: there is no explanation of a contingent fact, and there is no good reason to accept this. 

-Example: an iPhone pops into existence without any cause whatsoever. 

-Example: an iPhone is produced without preexisting materials.

2. Unobjectionable: there is no sufficient reason for a contingent fact, but there is a good independent reason to accept this.

(a) Assuming that x has a sufficient reason for its existence or occurrence leads to an apparent absurdity. 

-Example: Such an assumption entails that everything exists or obtains of absolute 
necessity, that we lack free will, that quantum indeterminacy isn't real, etc.

(b) Assuming that x has a sufficient reason for its existence or occurrence conflicts with other things we have reason to accept. 

-Example: Such an assumption conflicts with (say) a priori and/or a posteriori evidence that no being is  metaphysically necessary.

Here's my claim: Positing that there is no sufficient reason for why an independent being exists beyond the factual necessity of its own nature, and is thus a brute fact, is of an unobjectionable sort. In particular, it's a brute fact of type 2(b), since assuming the contrary conflicts with something else that we have reason to believe, viz., that no being is metaphysically necessary. Here are three reasons one might offer for thinking that no being is metaphysically necessary: 

(i) Modal evidence: We have modal intuitions that for any being, there are worlds at which it doesn’t exist.

(ii) Abductive evidenceour extensive experience of an extremely wide variety of concrete objects is such that we find them all to be contingent. What explains this? The simplest, most conservative explanation of the data with the widest explanatory scope is the hypothesis that all concrete objects are contingent beings. 

(iii) Origin essentialism: Widely shared intuitions support the Kripkean thesis that objects have their origins of metaphysical necessity: for any world W and objects x, y, and z, if x was produced by y and z at W, then x was produced by y and z at every other world W' at which x exists. So by implication, if an eternal universe lacks an origin at the actual world, then it lacks an origin at every world. And if that's right, then it's metaphysically impossible for such a universe to have a further explanation for its existence. 

For at least these reasons, then, the existence of a factually necessary universe is unobjectionably brute, since assuming the contrary conflicts with other things we have reason to accept. 

Craig On Causal Candidates for the Origin of the Universe

(Very rough draft)

Leaving aside formal and final causes, there appear to be four possible scenarios for the origin of our universe:

(i) Both an efficient cause and a material cause
(ii) An efficient cause without a material cause
(iii) A material cause without an efficient cause
(iv) Neither an efficient nor a material cause

Now William Lane Craig thinks (iv) is prima facie implausible, and so the position of last resort. However, it should be noted that even Craig grants that (iv) is unobjectionable if the universe is a 4-dimensional block of some sort. But the worry is that many scientists and philosophers think that ours is such a universe.  Many will therefore part company with Craig at this early stage of his argument. However, let's waive this objection for the moment, and grant, arguendo, that Craig is right. Now Craig  ultimately wants to argue that (ii) is the most probable candidate scenario for the origin of the universe. What about the other options?

One might think that, prima facie, (i) is the most natural to assume as a starting point. Indeed, Craig seems to agree. However, Craig has argued that (ii) is the most plausible, on the grounds that our best scientific models indicate that there was an absolute beginning to the expansion of all physical reality, including the multiverse, if such there be. Craig thinks this is supported by the Borde-Guth-Vilenkin theorem.

At this point, one might quite reasonably object that a beginning to the expansion of the universe (or multiverse) doesn't entail a beginning to the existence of the universe (or multiverse). For the universe could've existed in a quiescent state. However, Craig has argued that such a purely naturalistic quiescent universe can be ruled out on the grounds that it would be in an state of absolute rest, from which no event could arise (barring supernatural intervention). However, Wes Morriston has argued persuasively that a similar worry arises for the hypothesis of the creation of the universe by a God who is quiescent prior to the creation of the universe. If so, then neither the theistic hypothesis nor the quiescent naturalistic universe hypothesis has an epistemic advantage over the other. Therefore, (iii) seems to be at least on an epistemic par with (ii).

To add to this debate, I'd push the point further and argue that if (ii) and (iii) really were the two most plausible candidates, (iii) has an epistemic advantage over (ii), on the grounds that we have strong a priori and a posteriori reasons for thinking that a version of the principle of material causality (PMC) is true, and thus that creation ex nihilo is metaphysically impossible. Indeed, it looks as though PMC provides roughly equal grounds for preferring just about any of the other candidates over (ii). However, given the prima facie oddity of a universe arising from an absolutely quiescent state, candidate (i) (i.e., matter/energy, or its ultimate constituents, are eternal, and thus that our universe arose from prior materials) and candidate (iv) (in particular, an eternal 4d block universe) appear to have an epistemic advantage over both (ii) and (iii).

Sunday, November 01, 2015

Book Symposium on Metz's Meaning in Life

Thaddeus Metz's account of meaning in life is the focus of the October 2015 issue of The Journal of Philosophy of Life. The journal have kindly collected all of the papers into an open access book, which can be found here.
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