I am very confident that the oft toted principle of sufficient reason that theists tend to make, is self refuting: trying to apply it will necessarily lead to either an infinite regress of contingent explanations, or a brute fact, which is to say the PSR can't meet its own standard, not even when god is applied. (See here and here and here.)
Many Catholic theists themselves have recognized this and that's why they have to use a watered down version of the PSR to try and save them from this self refutation. But they technically can't. There's no way out of the problem. I will explain why by demonstrating this problem with a crazy Catholic apologist I sparred heavily with a few months ago over on the Strange Notions website.
This is taken from a comment of a Catholic apologist quoting Edward Feser.
Now, I'm quoting him quoting Edward Feser, so I cannot guarantee accuracy of Feser's words. But I will take them as they are and assume they are accurately quoting Feser. Here's my response:
If your god can't meet the standards of the PSR, as stated by Feser himself, or that I've stated, you have no claim to say god is necessary—metaphysically or otherwise.
Here is the explanation Feser gives for his definition via Peter Weigel.
If your god can't meet the standards of the PSR as stated by Feser himself or that I've stated, you have no claim to say god is necessary, metaphysically or otherwise concrete extant objects and their arrangements... The demands of his model are thus notably different in scope from what in Leibniz is the principle of sufficient reason, in which the phenomena to be explained include propositions. As Leibniz presents the principle, every fact and every true proposition -- at least every contingent proposition -- must have an explanation. What is sufficient reason furthermore assures the truth of what it explains... Hence Leibniz’s rendition has a logical cast to it, whereas Aquinas is not fishing for reasons for every logically contingent proposition. For Aquinas, to say X explains or accounts for Y is not to say it necessary [sic] entails it (when Aquinas is talking about real-world causation). Aquinas thus in his model cautiously keeps in view the explanation of the existence of objects, not reasons for literally everything. Aquinas thinks truth and falsity always accrue to individual beliefs in minds. Propositions for him are thus beings of reason and do not exist as disembodied abstracta, so they are not things out there to be explained in the manner real beings are. (Weigel 2008, pp. 128-29)
Feser goes on to explain:
This point is crucial for understanding why some objections to the rationalist construal of PSR do not apply to PSR as understood by Scholastic writers. For example, one well-known objection to PSR asks us to consider the proposition comprising the conjunction of all true contingent propositions. Since each of its component conjuncts is contingent, this big proposition is contingent. In that case, the explanation of this big proposition cannot be a necessary proposition, for whatever is entailed by a necessary proposition is itself necessary. But neither can its explanation be a contingent proposition. For if it were, then that contingent proposition would itself be one conjunct among others in the big conjunction of contingent propositions. That would mean that the big conjunctive proposition explains itself. But the PSR tells us that no contingent proposition can explain itself. So, the big conjunctive proposition cannot have an explanation. But in that case there is something without an explanation, and PSR is false. (Cf. Ross 1969, pp. 295-304; Rowe 1997; Rowe 1998; Van Inwagen 1983, pp. 202-4; and the critical discussions in Gerson 1987 and Pruss 2009, pp. 50-58) From a Scholastic point of view this sort of argument is a non-starter, since on the Scholastic understanding of PSR, propositions are not among the things requiring explanation in the first place, and explanation does not require logical entailment.- Feser SCHOLASTIC METAPHYSICS. [Emphasis in original]
Now, I'm quoting him quoting Edward Feser, so I cannot guarantee accuracy of Feser's words. But I will take them as they are and assume they are accurately quoting Feser. Here's my response:
If your god can't meet the standards of the PSR, as stated by Feser himself, or that I've stated, you have no claim to say god is necessary—metaphysically or otherwise.