Thomas Nagel writes a review of Alvin Plantinga’s recent book, Where the Conflict Really Lies, which James Beebe has also nicely reviewed here at Prosblogion.
Nagel’s review is well-written and charitable. He covers much territory by summarizing large swathes of Plantinga-philosophy in succinct paragraphs, all without sacrificing accuracy. (He even appears to have carefully read footnotes from Plantinga’s other works.) His only objection seemed to be that Plantinga does not consider naturalist theories of mental content. Plantinga doesn’t cover them in this book, but he deals with a number of them in a recent PPR paper.
So, as one very familiar with Plantinga’s work, I was impressed with Nagel’s review.
Let ‘PSR’ stand for the principle that whatever is, but need not be, has an explanation for its being.
(PSR) Whatever obtains, but doesn’t obtain of necessity, has an explanation for its obtaining.
Equivalently: Every contingent state of affairs has an explanation.
One might think that PSR has both a priori and empirical support. Regarding the a priori, when we consider an arbitrary state of affairs that obtains but doesn’t have to obtain, we feel motivated to wonder why it obtains; and that wonder seems to reveal an inclination in us to think there ought to be an explanation.
As for empirical support, PSR is a simple (the simplest?) explanation of all the cases of explanation anyone has encountered.
The support is defeated, however, if there are counter-examples to PSR. And, my sense is that most philosophers these days think or suspect or worry that there are counter-examples.
Perhaps the most commonly cited counter-examples are these: (1) quantum events, and (2) the Biggest Contingent Fact. It turns out to be difficult, however, to get these counter-examples to stick, as I’ll attempt to explain. I’ll focus more on (2), since I take it to be the more serious candidate.