In summary, then, orthodox Trinitarian theology claims:
A. The doctrine of the Trinity is coherent and intelligible in itself.
B. The human mind is nevertheless too limited adequately to comprehend it.
C. The doctrine could, accordingly, never have been arrived at via purely philosophical arguments.
D. We can nevertheless be rationally justified in affirming it on the basis of testimony.
E. We can show that no attempt to prove the doctrine self-contradictory succeeds.
F. We can arrive at a limited understanding of the doctrine via various analogies.
As I have also noted previously, the conception of the Trinity as a “mystery” finds a parallel in the view of some contemporary philosophers of mind (e.g. Colin McGinn) that while an adequate naturalistic explanation of consciousness exists, our minds are too limited to understand it. This view even goes by the name “mysterianism,” and it is motivated not only by a desire to sidestep the various philosophical objections to materialism, but also by the idea that natural selection is unlikely to have shaped our minds in a way that would allow us to discover everything there is to know about the world. It is far more likely, mysterians contend, that the contingent forces of evolution so molded our cognitive faculties that they are useful only for understanding a fairly narrow range of truths, and that there are barriers beyond which they cannot push. This is certainly a very reasonable view to take if there are good reasons to think naturalism is true in the first place. (There aren’t, but let that pass for the moment.)
For a very useful overview of traditional Scholastic thinking on this subject, see Joseph Pohle and Arthur Preuss, The Divine Trinity: A Dogmatic Treatise, an old theological manual that can be acquired from various reprint publishing houses (e.g. here’s one version) and is also available via Google books. Chapter IV, section 1 provides an account of the sense in which the doctrine is a mystery (and, so we Catholics maintain, must be held to be a mystery, on pain of heterodoxy). When that claim is properly understood, it is, I maintain, perfectly clear that the skeptic has no grounds for dismissing the doctrine of the Trinity simply because it is held to be a mystery. He might want to reject it on other grounds, but there is no basis for holding that affirming a “mystery” (again, in the specific sense in question) is per se contrary to reason.
In recent weeks there has been a fair bit of discussion of the Trinity in the blogosphere – specifically, at Bill Vallicella’s blog, at The Smithy, and (naturally enough) at Dale Tuggy’s Trinities blog. In a post from yesterday, Dale objects to my claim (in the first of the two earlier posts linked to above) that the doctrine of the Trinity is implied by the New Testament. Just to clarify, contrary to what Dale supposes, I did not claim that the “creedal formulas” were logically implied by the New Testament. What I was claiming is that the following statements, which form the core of the doctrine, are implied by it:
1. The Father is God.
2. The Son is God.
3. The Holy Spirit is God.
4. The Father is not the Son.
5. The Father is not the Holy Spirit.
6. The Son is not the Holy Spirit.
7. There is exactly one God.
That is different from claiming that formulas like “three Persons in one substance” are implied by the New Testament. To be sure, I’m not saying they aren’t implied by it; one could argue that they are implied indirectly, insofar as (1) – (7) are implied by the New Testament, and the creedal formulas are in turn implied by (1) – (7). But that wasn’t my point in the post in question, and the point I was making stands whether or not one wants to accept that further claim. As long as (1) – (7) alone are implied by the New Testament, that suffices to show that the doctrine of the Trinity (at least in a rudimentary form) is implied by the New Testament, or so I would claim.
(I like the illustration Dale uses, BTW. [Slightly to alter Codgitator’s combox paraphrase of Andrew Meyer: “Don’t Feser me, bro!”] Dale and I were at Claremont Graduate School together, and have, I suppose, been arguing about the Trinity on and off for over 15 years. The funny thing is, when we started arguing I was still an atheist and attacked the doctrine – two of my earliest published articles were critical of Trinitarianism – while Dale defended it. Now I’m a reactionary Catholic who insists on upholding every jot and tittle of the creeds, while Dale has in recent years taken a more flexible approach. Funny old world.)
Meanwhile, Bill Vallicella today suggests that the Trinitarian shoots himself in the foot by adopting a “mysterian” line, precisely because he thereby legitimizes the naturalist – whose views are inconsistent with Trinitarianism since they are incompatible with theism – in taking the same approach toward the defense of his own position.
In response, I want to take issue first with Bill’s characterization of the appeal to “mystery.” He says: “The (positive) mysterian maintains that there are true propositions which appear (and presumably must appear given our 'present' cognitive make-up) contradictory.” But that is not what Trinitarian theologians mean when they affirm that the doctrine of the Trinity is a mystery. Since (as I noted above) they affirm that it can be shown that no attempt to prove the doctrine self-contradictory succeeds (again, see Pohle and Preuss), they do not hold and cannot hold that the doctrine when rightly understood “appears contradictory,” much less that it must appear contradictory. They maintain instead that we cannot fully comprehend it; and that is a very different claim.
Think of it this way: The Trinitarian theologian maintains that the Trinitarian propositions (1) – (7) listed above are perfectly consistent when rightly understood, so that if any reading of them seems self-contradictory, then that reading is mistaken, and does not accurately convey what the doctrine says. Hence if the doctrine “appears contradictory” to you, you have by that very fact misunderstood it and are not really entertaining it at all. At the same time, if you give these propositions an alternate reading on which their consistency is entirely transparent, you have no doubt fallen into some heresy or other. So, the right thing to say would seem to be this: “Mysterianism” with respect to the Trinity entails, not that (1) – (7) appear or must appear contradictory, but rather that their meaning is not entirely apparent in the first place. The Trinitarian does not say: “I clearly see what the propositions are saying, and they seem contradictory” but rather “I do not see any contradiction between them, but then I do not see clearly what they are saying in the first place.” (There is nothing inherently objectionable in affirming a proposition or set of propositions that one does not fully understand. Even many people – and surely most philosophers – who have enough of a grasp of relativity theory or quantum mechanics to be able to say that their acceptance of these theories is not based entirely on the authority of physicists would have to admit that their comprehension of them is nevertheless very sketchy at best.)
In any event, Bill’s objection seems to be that since the appeal to “mystery” could be used in defense of incompatible positions – naturalism and Trinitarian theism – there is something fishy about it. Now, I’m not entirely clear about what the problem is. Modus ponens can also be used in defending incompatible positions. Does that mean there is something fishy about modus ponens? Obviously not. But maybe what Bill has in mind is the idea that the appeal to mystery would leave naturalism and Trinitarian theism at a kind of argumentative stalemate: Anything the naturalist could say against the Trinitarian theist could be rebutted with an appeal to theological mystery, and anything the Trinitarian theist could say against the naturalist could be rebutted with a mysterian appeal to the cognitive limitations imposed by natural selection. Even if this were true, though, it is hard to see how this by itself shows that either the Trinitarian’s appeal to mystery or the naturalist’s appeal to it is false, unjustified, or in any other way rationally objectionable – as opposed to just leaving us in a very unsatisfying epistemic situation.
In any case, I don’t think it is true. In particular, I don’t think there is any parity between the Trinitarian and naturalist appeals to mystery in the first place. I think that we can show that whatever one ultimately wants to say about it, the naturalist’s appeal to mystery is at least prima facie far less plausible than the Trinitarian’s appeal to mystery.
Consider first that, at least on the conception of God enshrined in classical theism (especially, I would say, as interpreted within Thomism) it is quite obviously far more plausible to suppose that God should be incomprehensible to us than that the relationship between matter and consciousness should be. If God exists, then He is Pure Actuality, ipsum esse subsistens or Subsistent Being Itself, absolutely simple, and thus beyond the classifications by means of which we understand the things we can understand. He is not one object among others within the world but that which sustains all objects in being, from outside any possible world. What we say of Him is true not univocally but analogically. Etc. Neither matter nor consciousness is anything remotely like this. Instead, they are both conceptually and epistemically far closer than God is to the things we suppose we can understand. Hence there is prima facie a much stronger case for supposing that God’s nature should be incomprehensible to us than there is for saying that the relationship between matter and consciousness should be. God is precisely the sort of thing we should expect to be unable fully to understand, while matter and consciousness are not (even if it turns out that we cannot fully understand them either).
Consider further that there is nothing in the Trinitarian’s appeal to mystery that tends to undermine the power of reason itself, while there is such a tendency in the naturalist appeal to mystery. For as we have noted, the latter sort of appeal typically rests on the idea that the contingent circumstances of human evolution are bound to have made our cognitive faculties suited only to uncover certain truths and not others. But why assume it suited them to uncover any sort of truth at all? As the “argument from reason” defended by Victor Reppert, William Hasker, Alvin Plantinga, and others suggests, there are strong grounds for thinking that regarding our cognitive faculties as the products of purely natural processes like evolution undermines their reliability. For natural selection favors fitness, and there is no guarantee that this correlates with truth. Obviously, naturalists might try to reply to the argument from reason in various ways. The point is that the specific grounds a naturalist might appeal to in order to provide independent motivation for his appeal to mystery – independent, that is, of a desire to sidestep arguments against naturalism – at least threaten to undermine reason in general. The Trinitarian says: It is primarily God’s nature that puts limits on reason’s power to comprehend the Trinity. The naturalistic mysterian says: It is primarily the way in which our minds came about that puts limits on reason’s power to comprehend consciousness in materialistic terms. The latter claim is prima facie far more likely to undermine reason as such than the former is.
Then there are the grounds we have for rejecting any materialist account of the mind, grounds which are simply not at all plausibly rebutted by an appeal to mystery. While there are many reasons for denying that the mind can be explained in materialist terms, the main reason from an Aristotelian-Thomistic point of view has to do with the nature of the intellect’s activity in grasping the forms or essences of things. In particular, forms and our thoughts about them are precise, exact, or determinate in a way no material thing can be even in principle; and forms are universal while material representations are necessarily particular. Hence to grasp a form cannot in principle be to have a material representation of any sort.
I have discussed this line of argument in earlier posts – here and here, for example – and in print in several places. Interested readers are referred to The Last Superstition, pp. 123-126; Aquinas, pp. 151-159; and the chapter on Intentionality in Philosophy of Mind. (They ought also to read James Ross’s article “Immaterial Aspects of Thought.”) The point to note for now is that it is hard to see how an appeal to mystery, specifically, could plausibly enable the naturalist to avoid the force of such arguments. To say:
Maybe consciousness really is physical and we just can’t understand, given our cognitive limitations, how something can be both conscious and physical at once.
is one thing. There is no explicit self-contradiction or absurdity in that claim. (I think there is an implicit one, but leave that aside.) But to say either:
Maybe determinate phenomena are really indeterminate and we just can’t understand, given our cognitive limitations, how something can be both determinate and indeterminate in the same respect at the same time.
Maybe universals are particular and we just can’t understand, given our cognitive limitations, how something can be both universal and particular.
is just to spout nonsense, for both of these statements are self-contradictory. And it will hardly do to appeal to a self-contradiction as a way of deflecting the claim that one’s position is incoherent.
Last but by no means least, the reason the Trinitarian has for affirming his doctrine is, of course, an appeal to divine authority. And if the doctrine really is divinely revealed, then (since God is infallible) it must be true. By contrast, the naturalist has by his own admission only his own extremely limited powers of observation, theorizing, etc. to justify his naturalism. Surely an appeal to Infallible divine revelation plus mystery is more plausible than an appeal to Limited human powers of observation, theorizing, etc. plus mystery. Obviously, the skeptic will deny that Trinitarianism really has been divinely revealed, but that is beside the point. The point is rather that the best-case scenario for the Trinitarian – the revelation really did occur – gives him about as good a reason as one could possibly want (infallible testimony) for believing that his position is correct, whereas even the best-case scenario for the naturalist – his faculties of observation, theorizing, etc. are functioning normally, he is reasonably well-informed, and so forth – still leaves him very far short of having an infallible source of information to appeal to. The overall Trinitarian position thus makes an appeal to mystery more credible than the overall naturalist position does, even if the latter appeal has some credibility.
So, again, the two views are not on a par. However prima facie plausible a naturalist appeal to mystery might be, in the nature of the case it cannot be as plausible as the Trinitarian’s appeal to mystery. Hence Bill is mistaken in thinking (if this really is what he thinks) that their respective appeals to mystery put the naturalist and the Trinitarian at an epistemic stalemate. (Of course, by itself that does not show that of the two views, Trinitarianism is the correct one – that is a different question.)
UPDATE 2/13: I've posted a follow-up here.