To live today as a follower of Christ is to be exposed to the question of certainty. Can we really be certain that the Faith comes from God? Can we come to accept, without qualification, doubt, or intellectual distance, that Jesus’ teaching was an authentic revelation? The apparent secularization of the West, the feeling that all beliefs are contestable, and an ambient modesty about the human intellect’s ability to know truth all combine to challenge certainty on such matters for those living in the West in the 21st century.

Bl. John Henry Cardinal Newman’s work An Essay in Aid of a Grammar of Assent sheds light on how we might approach aspects of this issue. Bl. Newman wrote the Grammar later in life, and it examined a topic he had long wanted to treat: certainty in religious belief. According to Fr. Philip Flanagan, (see footnote 1 below) the Grammar of Assent ought to be read in light of a correspondence Newman carried on with William Froude, a scientist and a friend of Newman’s. The two corresponded about the question of unqualified belief. Froude’s wife and four of their children became Catholics, but Froude himself never did, and a sticking point for him was what he perceived to be the gap between the absolute acceptance of Catholicism that Catholics held and the evidence adducible for Catholicism, which could never be such as to remove all admixture of doubt. Perhaps Catholicism was probable, even highly probable—but how could one ever be so certain of it as to believe without qualification that it is true?

In Flannigan’s telling, Froude held that one could only be certain of something that was either self-evident, or provable by “mathematical demonstration.” Thus he believed that absolute certainty was not possible in ordinary life, politics, history, and theology—and yet Catholics are expected to be certain in their adherence to the Catholic faith.

Locke and Newman

In the Grammar of Assent, Newman offers a critique of this theory by Froude, and he does so, as Fr. Flannnigan notes, by his discussion of John Locke; Locke serves as a proxy for Froude’s epistemology in the Grammar.

Newman’s critique of Locke involves what Newman calls assent. For Newman, “assent” means a mental act that is “in itself the absolute acceptance of a proposition without any condition.” The path to such unconditional adherence, for Newman, passes through inference; Newman calls the act whereby we argue or supply evidence for a proposition “inference” and inference is always strictly “dependent” on the premises from which it proceeds. Assent follows inference, but transcends it, as it is a mental adherence that is unconditional. Assent is not a different way of referring to the same mental act of inference, but a different mental act, one that is not strictly tied to the reasoning involved in inference and simply holds that a given proposition is true. It does not allow for degrees; though an assent may be more or less “vivid,” strictly speaking we don’t give more or less assent to something. Either we assent (which is an absolute act) or we do not assent. (2)

According to Newman, Locke, however, holds a general theory in which assent does admit of degrees—that is, we give a stronger or weaker assent to propositions based on the evidence for them. For Locke, we should “not [entertain] any proposition with greater assurance than the proofs it is built on will warrant.” (3) In critiquing this view, Newman notes that not even Locke consistently holds to it, for he allows for exceptions to his own rule:

‘Most of the propositions we think, reason, discourse, nay, act upon, are such as we cannot have undoubted knowledge of their truth; yet some of them border so near upon certainty, that we make no doubt at all about them, but assent to them as firmly, and act according to that assent as resolutely, as if they were infallibly demonstrated, and that our knowledge of them was perfect and certain.’

So says Locke. Newman comments on this passage, stating that Locke here admits that there are cases in which inferences do not arrive at a certain conclusion, and yet we treat them as if they had.
“That is,” writes Newman, “he affirms and sanctions the very paradox to which I am committed myself.” Newman’s other quarrel with Locke is, then, over the scope of cases in which that kind of mental process is legitimate. According to Newman, Locke only allows for assent in certain circumscribed cases, in what Newman sees as an arbitrary limitation:

Instead of going by the testimony of psychological facts, and thereby determining our constitutive faculties and our proper condition, and being content with the mind as God has made it, he [Locke] would form men as he thinks they ought to be formed, into something better and higher, and calls them irrational and indefensible, if (so to speak) they take to the water, instead of remaining under the narrow wings of his own arbitrary theory.

That is, Newman thinks we must break from Locke in allowing much greater scope for the lawfulness of assent in many cases where some proposition has not been “infallibly demonstrated.” As Newman sees it, human beings do, as a matter of fact, arrive at such assent in many matters in which proof does not rise to the level of demonstration (either because demonstration, although possible, simply has not been done in a certain case, or because demonstration is not possible). We believe with certainty in historical matters, for example.

For Newman, then, assent is a fact of our existence and natural to us. “We do but fulfill our nature in doubting, inferring, and assenting; and our duty is, not to abstain from the exercise of any function of our nature, but to do what is in itself right rightly,” Newman writes early in the Grammar. And, while addressing Locke’s theory, he puts it thusly: “…[H]e [Locke] consults his own ideal of how the mind ought to act, instead of interrogating human nature, as an existing thing, as it is found in the world.” Consequently, for Newman, we should look to the nature of our minds and, allowing our minds to work according to it, welcome assent, as much as (for example) inference, as part of how we engage intellectually with the world.

Religion, Natural and Revealed

A skeptic of a certain stripe might argue that even if Newman’s epistemology works for ordinary matters, it’s out of court simply to transfer that theory over to the religious domain, since “extraordinary claims demand extraordinary evidence.” But if the human mind works by passing through inference to assent as a general matter, this is also, for Newman, how it works when it comes to religious questions like whether Christianity comes from God.

In the second part of the Grammar, Newman gives account of some of the personal reasons that lead him to belief in the divine origin of Christianity, providing a sort of example of his own thinking in action when applied to the question of the credibility of the claim that Christianity relays an authentic divine revelation. The arguments, which need not be gone into here, range from the fate of Judaism after the rejection of Christ by Israel to the conversion of the ancient pagan world to Christianity. But Newman prefaces these arguments with a helpful methodological note: Arguments for Christianity will not appear convincing to those who are not adherents of what Newman calls “natural religion,” which is the proper religious sense of mankind apart from the specific divine revelation imparted with Christianity:

I have no scruple in beginning the review I shall take of Christianity by professing to consult for those only whose minds are properly prepared for it; and by being prepared, I mean to denote those who are imbued with the religious opinions and sentiments which I have identified with Natural Religion…. It is plainly absurd to attempt to prove a second proposition to those who do not admit the first.