On what seems to be the earliest page of the New Testament writings, the Apostle Paul says that the faith comes to us in "full assurance"--plerophoria (1 Thessalonians 1:5). This is Christian theology's first mention of certitudo fidei.
It was inevitable, I suppose, that this certitude of faith would in due course be studied within the categories of comparative epistemology, with its preoccupation with "how do I know it?" and "how sure can I be?"
Whereas modern apologetics would reduce faith's certitude to Quine's "web of belief," which strikes me as no more than a strong opinion buttressed by carefully placed evidence viewed from carefully selected angles, traditional Christian theology considers the certitude of faith to be the highest level of certainty possible to man in this world. Indeed, Christian theology has traditionally claimed that the light of faith affords a certainty even stronger than that of logic.
This claim calls for some effort at distinctions, I believe. First, inasmuch as the truths of faith are open to rational doubt, reason itself, in applying its own rules, cannot regard faith as providing a high level of certitude. How can one regard as "certain" any proposition open to doubt? Thus, considered within the usual standards of epistemology, the certainty of faith cannot rank very high, which is apparently why modern apologetics tends to shove it almost completely into the realm of psychology, speaking of a "web of belief."
Second, however, if we consider certainty, not from the perspective of intellectual clarity, but from the viewpoint of action, hardly any truth logically perceived can measure up to the certainty of faith. Although Camus speculated that the day may dawn on which, if a man insisted that the addition of two and two equals four, he would be shot for it, I rather doubt that most men, faced with that choice, would go on insisting that two and two make four. Simply put, this is not the sort of truth that evokes loyalty. Most men, one suspects, would rather deny a mathematical truth than be shot for affirming it.
It is not as though logical and mathematical truths are not truths of action. Indeed, all the time men do act on the truths of mathematics and logic, as well as the conclusions that science attains through experiment and empirical evidence. Still, these truths do not evoke from the heart that sense of loyalty elicited by the truths of faith. This loyalty, I think, is not separable from certainty. The martyrs did not die in a state of doubt.
Now a truth for which men will die is more certainly known than a truth for which men are not willing to die, even though the former is subject to doubt, whereas the latter may not be. The certainty for which a man will live, suffer, and die is of a very different order from the certainty available to logic, mathematics, and science. It is closer to what we call personal trust, as when we say we are "sure" of somebody. But it is even more than that. It is a certainty shaped in the context of love and the union that love brings about.
The certitudo fidei is more compelling, more "active," I suspect, for two reasons:
First, whereas the truths of logic, mathematics, and science are able to stand by themselves, strong and clear, independent of my assent, indifferent to my notice, imperious in their claims, relentless in their assertions but in no way dependent on my adherence, the truths of faith are what we may call "invitational," humbler in their approach to my mind, more clearly interested in my hopes, gentler and more compassionate to my fears, holding out greater blessings for me to anticipate, and explicitly promising a rich recompense for my fidelity.
It is the great merit of rational truths, and the solid foundation for their claims, that they are actually seen, even to the point that precludes their conscientious denial. There is nothing irrational or risky about their authority. At the same time, they promise nothing more than themselves, nothing beyond "more of the same."
Indeed, if rational and scientific truths are perceived to address our hopes, they really can become rivals of the truths of faith, and nowadays it is not uncommon to see folks placing their trust in things like mathematics and the advance of chemistry. The problem with this approach is that everything promised will simply be "more of the same." I recently saw an advertisement promising, "Great Sex Till The Day You Die." Yes, well, so what?
Second, the truths of faith are inseparable from hope concerning things unseen. They do not promise "more of the same." By pointing our minds to the unseen and the future, in fact, they implicitly call into question any life not based on their promise. Indeed, if the matter of their promise is not addressed, the truths of faith hint at a danger to the soul, even its loss. Mathematics will never do that to you. Mathematics never does you the kindness of a threat, even though it certainly does punish those who ignore it.
Rational truth proclaims that if A is larger than B, and B is larger than C, then A is larger than C. Well, big deal.
The truths of faith proclaim, "him who comes to Me I will in no wise cast out." Now, this really is a big deal.
Subscribe to Pastoral Ponderings — Fr. Reardon's weekly essay.
Read past essays and listen to podcasts by Fr. Reardon.
Books by Fr. Reardon: