A reader claims that "to affirm that there are contingent beings just is to affirm that they have that whereby they are, namely, a cause." This implies that one can straightaway infer 'x has a cause' from 'x is contingent.' My reader would agree with Reginald Garrigou-Lagrange who, taking the traditional Thomist position, maintains the following Principle of Causality (PC):
. . . every contingent thing, even if it should be ab aeterno, depends on a cause which exists of itself. (Reality: A Synthesis of Thomistic Thought, tr. Patrick Cummins, O. S. B., Ex Fontibus 2012, p. 62)
So even if the physical universe always existed, and therefore never came into existence, it would nonetheless require a cause of its existence simply in virtue of its being contingent. I find myself questioning both my reader and Garrigou-Lagrange. For it seems to me to be conceivable that an item be contingent but have no cause or ground of its existence. This is precisely what Garrigou-Lagrange denies: "contingent existence . . . can simply not be conceived without origin, without cause . . . ." (p. 63)
But it all depends on what we mean by 'conceivable' and 'contingent.' Here are my definitions:
D1. An individual or state of affairs x is conceivable =df x is thinkable without formal-logical contradiction.
Examples. It is conceivable that there be a mountain of gold and a tire iron that floats in (pure or near-pure) water. It is conceivable that I jump straight out of my chair, turn a somersault in the air, and then return to my chair and finish this blog post. It is inconceivable that I light a cigar and not light a cigar at exactly the same time. As for formal-logical contradiction, here is an example: Some cats are not cats. But Some bachelors are married is not a formal-logical contradiction. Why not? Because its logical form has both true and false substitution instances.
D2. An individual or state of affairs x is contingent =df x is possibly nonexistent/nonobtaining if it exists/obtains, and possibly existent/obtaining if it does not exist/obtain.
The contingent is that which has a certain modal status: it is neither necessary nor impossible. For example, me and my cigar are both contingent beings: neither is necessary and neither is impossible. My smoking the cigar now is an example of a contingent state of affairs: it is neither necessary nor impossible that I smoke a cigar now. The type of modality we are concerned with is broadly logical, not nomological.
Now is it conceivable that something exist contingently without a cause? It seems so! The nonexistence of the physical universe is thinkable without formal-logical contradiction. The physical universe is contingent: it exists, but not necessarily. Its nonexistence is possible. Do I encounter a formal-logical contradiction when I think of the universe as existing without a cause or explanation? No. An uncaused universe is nothing like a non-triangular triangle, or a round square, or a married bachelor, or an uncaused effect. Necessarily, if x is an effect, then x has a cause. It is an analytic truth that every effect has a cause. The negation of this proposition is: Some effects do not have causes. While this is not a formal-logical contradiction, it can be reduced to one by substituting synonyms for synonyms. Thus, Some caused events are not caused.
Contrary to what Garrigou-Lagrange maintains, it is conceivable that the universe exist uncaused, despite its contingency. If one could not conceive the uncaused existing of the universe, then one could not conceive of the universe's being a brute fact. And 'surely' one can conceive of the latter. That is not to say that it is possible. There is a logical gap between the conceivable and the possible. My point is merely that the 'brutality' of the universe's existence is conceivable in the sense of (D1). To put it another way, my point is that one cannot gain a a priori insight into the necessity of the universe's having a cause of its existence. And this is because the Principle of Causality, if true, is not analytically true but synthetically true.
Of course, if one defines 'contingency' in terms of 'existential dependence on a cause' then a thing's being contingent straightaway implies its being caused. But then one has packed causal dependency into the notion of contingency when contingency means only what (D2) says it means. That has all the benefits of theft over honest toil as Russell remarked in a different connection.
Garrigou-Lagrange thinks that one violates the Law of Non-Contradiction if one says of a contingent thing that it is both contingent and uncaused. He thinks this is equivalent to saying:
A thing may exist of itself and simultaneously not exist of itself. Existence of itself would belong to it, both necessarily and impossibly. Existence would be an inseparable predicate of a being which can be separated from existence. All this is absurd, unintelligible. (p. 65)
Suppose that a contingent existent is one that is caused to exist by a self-existent existent. If one then went on to say that such an existent is both contingent and uncaused, then one would embrace a logical contradiction. But this presupposes that contingency implies causal dependency.
And therein lies the rub. That the universe is contingent I grant. But how does one get from contingency in the sense defined by (D2) supra to the universe's causal dependence on a causa prima? If one simply packs dependency into contingency then one begs the question. What is contingent needn't be contingent upon anything.