One of the greatest Catholic thinkers of the twentieth century was Fr. Herbert McCabe. He is also one of the most underappreciated.

Though he was a Dominican and (naturally as such) greatly influenced by St. Thomas Aquinas, it is said by those who know his work best that he was rather uncomfortable being called a “Thomist.” In the words of his literary executor Brian Davies, “He had a horror of being called a ‘Thomist’” Why? Because, in a sense, he thought the only true Thomist could be Aquinas himself, and that a philosopher’s chief authority can never really be another philosopher, it can only be reason. And for the Christian philosopher, it must be reason and God—the two of which can never be in opposition. Yale theologian Denys Turner captures the essence of McCabe’s attitude when he writes, “Herbert was no ‘Thomist’ if a Thomist is someone who thinks about Thomas. He thought with Thomas.”

Though McCabe preferred not to be called a Thomist, he was certainly Thomistic. But uniquely, he also offered in his work an interesting amalgamation of Thomistic thought with that of modern philosophy (he was especially influenced by Ludwig Wittgenstein). This made him one of the most interesting Catholic philosophers of his generation.

McCabe had a style that was all his own, and he wrote with special attention to themes at issue “right now.” His concerns in the twentieth century were not much different than ours today. In fact, their relevance and urgency have only become more intensified over time.

Fundamental to his work in natural theology was his treatment of faith and reason as two distinct, yet cohering, ways of knowing.

“Faith is believing what you know ain’t so,” quipped Mark Twain. Though perhaps only offered with partial seriousness, this famous quote summarizes what many have come to believe today—namely, that faith is antithetical to reason. Herbert McCabe recognized this growing trend and was one of the great crusaders of his time against such errors.

Can faith be reasonless?

McCabe insists rightly that faith involves at least holding that a certain proposition is true; this is a necessary—but not sufficient—component of faith. Put another way, there is no such thing as believing something without believing it to be true. Saying “I believe that . . .” is synonymous with saying “I believe it is true that . . .” But as we’ll see, it involves more than that too.

Common conceptions of faith often presume too little about its intellectual integrity. And sometimes there is an overcompensation in the other direction. Some assume that reason and argument have nothing to do with faith, while others posit that reason and argument have everything to do with faith. The trick to getting faith right, says McCabe, is to rule out such erroneous conceptions first.

First, let us think about whether faith must involve reason. Try to conceive of what it would be like to believe something but with no reason whatsoever. Let’s call this reasonless faith. But here’s the cardinal difficulty with reasonless faith. A reasonless proposition p is by definition a statement held to be true for no reason. Imagine I ask you, “If you have no reason for believing p is true, then how do you know p is true?” If you believe by reasonless faith, you could only answer in one way. You could only answer, “I don’t.”

Reasonless faith and truth have no direct link. Holding something to be true requires reasons. We never believe something to be true for no reason. Imagine asserting that there are no golden retrievers in France. And imagine that you really believe it to be true. Could you really make the claim and believe it to be true—but for no reason at all? Even if your justification is terribly weak and irrational—say, because you love France and hate golden retrievers, and can’t bear the thought of both co-existing in one place—then you would still have a reason for your belief. This would be a case of wishful thinking, but even wishful thinking involves reasons.

So reasonless faith is out.

McCabe sums it up thusly: “If people were totally indifferent to any possible reasons for asserting or denying their proposition, we should think that they didn’t really hold it as true, but perhaps just liked the sound of the words expressing it.” But again, faith is (at the very least) to believe that something is true.

How reasonable can faith be?

There are also problems at the other extreme. McCabe writes, “If someone is so concerned with reasons for and against holding his or her proposition that the holding of it is entirely dependent on the reasons, we should begin to wonder why he or she claimed to have faith in it?”

There is something reminiscent here of G.K. Chesterton’s analysis, in his book Orthodoxy, of the man “who has lost everything but his reason.” The man who thinks only with his reason cannot be a man of faith. For Chesterton, the man who bases his beliefs wholly on reason winds up exhausted, attempting unwittingly to fit what is infinite into his finite mind. Any absolute prohibition of light from beyond the far side of reason leads to an intellect cramped and contracted—a mind far more dimmed than it ought to be. That was Chesterton’s take. McCabe drifts in the same direction.

The most rational among us reject neither faith nor reason, allowing each to assume its proper place in the life of the intellect. While faith without reasons make truth inapplicable, contends McCabe, faith entirely dependent on reasons makes faith inapplicable. So faith must be something in between. Here—as so often in Catholic theology—we see manifest an apparently “either/or” scenario that is really, in the final analysis, a “both/and.”

So faith is reasonable insofar as it is based on reasons; but it is not only based on reasons. It presses and expands reason to its limits, then pierces beyond the far side of reason, without deflating it in the process. Here, beyond the far side of reason, the whole human person—body, mind, and will—is moved to know with certitude that which cannot definitely be proven by reason alone. But how can such certitude be justified?

Faith is freeing

Faith does not corrupt reason. Faith, in fact, intensifies the natural light of human reason. It frees rather than constrains the powers of human rationality. Contrasting the Gentile intellect with that of those who have been redeemed in Christ, St. Paul writes, “They are darkened in their understanding, alienated from the life of God because of their ignorance and hardness of heart. . . . You were taught to put away your former way of life, your old self, corrupt and deluded by its lusts, and to be renewed in the spirit of your minds” (Eph. 4:18-23).

McCabe observes that when we believe by faith, we hold things to be true that we cannot prove. So there is an incongruence between 1) what our natural faculties of reason (i.e., sense perception, arguments, etc.) can prove and 2) what we know to be true. As we already implied above, by faith we become certain of more than we can prove. Sounds scandalous, right?

But if God exists (which may be known by arguments or more immediately by the interior witness of the Holy Spirit) then we are perfectly within our rights to believe what he reveals to us. In fact, we are obliged to accept what he reveals as true. As St. Thomas Aquinas writes, “Whereas an argument from human testimony is the weakest, an argument from the testimony of God is the strongest” (Summa Theologiae, 1.1.8). God can’t lie. He can’t err. He can only express what is. For he is the uncreated source of all created rationality.

But as McCabe reminds us, divine revelation is not restricted solely to what is in the Bible or promulgated through the teaching office of the Church. The consummate act of God’s revelation takes place in Jesus Christ, and in the communion of persons that Christ makes possible for us. Through this communion of persons, faith obtains its fullest form. It is far more than fulfillment of the intellect.

McCabe compares Christian faith to marriage. In knowing the love of his wife, a husband is certain about more than can be proved. His certainty is not the sort we would expect to be proved, for we understand that it rests on far more than a formula or syllogism. The faithfulness between husband and wife is like Christian faith because “both are a matter of personal relationship, and therefore involve will and decision.”

Faith, then, is a comprehensive act of the whole person. It often begins in the intellect (think of a first date when “gathering information” about the other is usually a large component). But faith also involves a kind of revealing that surpasses the intellectual. Thus the certitude of faith involves reasons, but it does not end with them.

All in all, faith begins and ends in an act of love by the infinite God. Eventually it involves a submission of the intellect—but a justified submission for the reasons we have said. And grace and faith are irrevocably related. “We are saved by grace through faith,” writes St. Paul (Eph. 2:8-9). Grace, being a free and unmerited gift of God, comes to us externally in the form of God’s revelation of himself through the Word of God, but also interiorly through the action of God within us, especially through the sacraments. The “spiritual physics” (to use Bishop Barron’s phrase) of faith are not subject to our analysis in the same way as, say, the mechanical functions of a pickup truck. But Herbert McCabe helps us to get at the mystery from some helpful angles—and he shows us that faith is not opposed to reason. At the very least, the distinctions he makes and the clarity he offers can assist us in dispelling the erroneous presumptions that far too many folks in our culture currently hold about the nature of religious belief.