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. 

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