It is a bit of a mystery that people are able to truly believe anything, since logic itself gives only conditional conclusions (“if A, then B”), and often reason fails even to go this far, but only that, given a number of premises, a certain fact is probable. The point is not that we can be mistaken in our reasoning and imagine that we have proven more than we really have, but that we can believe something while recognizing that we lack absolute proof. Some philosophers call this an error, or even a sort of moral fault, but how is it even psychologically possible? And yet, as Cardinal Newman points out, we have many such beliefs. There are common truths, such as (to take his examples) that England is an island and that I will die someday, for which I can produce strong arguments but would be impatient with a demand for absolute proof though I nonetheless assert absolute certainty. There is (another of his examples) our certitude of the law of inertia from converging probabilities: we can never find a body with absolutely zero force on it, but this is to be expected, and the better we are able to isolate a body, the better the law is found to hold, and it explains so much about our world. Newman’s goal is less to justify this sort of certitude than to describe it.
Thus he sharply distinguishes inference, in which a conclusion is accepted conditional on premises, from assent, which is unconditional. It is his claim that we are able to leap from the former to the latter. Assent itself may be notional or real. The former is purely intellectual assent, while the latter engages our imagination and emotions. It would thus be a mistake to think that the two assents are distinguished by their type of object (e.g. general vs. particular truths); the same proposition may be held either notionally or really. Newman clearly thinks that real assent is usually deeper and more motivating. When we say that the truth of a matter “really sunk in” or “really hit home”, we are describing what Newman would call notional assent becoming real.
As a Catholic cleric, Newman is concerned that our assent to the existence of God can be a real one. This is not obviously true. Philosophical arguments to an uncaused Cause, for example, leave us with only an intellectual construct that can be given notional assent. Thus Newman’s emphasis on our experiencing God via personal conscience. We experience not only approval or disapproval of certain acts; we also experience a sense of duty, and not conflicting moral duties but a single absolute and sovereign moral law. We naturally extrapolate this to a divine Lawgiver, unitary, all-holy, all-knowing, angered by our sins. The point here is not to logically prove the existence of God from our experience of conscience, but to clothe the intellectual object of God with something concrete enough to give the imagination and passions a hold on it. Many doctrines of the faith can in themselves hardly be held other than notionally, but Newman believes that we can have a real assent to the deposit of faith as a whole via a trust in the revelation God has given to His Church. I note in passing how odd it is that Newman never appeals to the sacraments as a way of imbuing intellectual doctrines with phenomenal “reality”.
Logic is limited by language, but Newman does not accept that the limits of my language are the limits of my world. We are able to reason nonlinguistically and supralogically, what he calls the “illative sense”. This is how we organize our knowledge and formulate the propositions that are the basis of logical analysis. It is how those with aesthetic taste or social tact are able to intuit accurately although they could never give satisfactory arguments. It is how the scientist or historian can recognize multiple lines of converging evidence as warranting a conclusion. That last example might seem different from the others, since it is not the manner of reasoning but the degree of certainty that outpaces articulated logic.
One might suspect that Newman has stuck in this method of “converging probabilities”, taken from Bishop Butler, among the powers of the illative sense because, like Butler, he needs it for apologetic purposes. Butler and Newman would reply that this sort of reasoning is as indispensable in every other enquiry as it is in religion. One might nevertheless insist that the leap to certainty, from inferring, say, probability = 0.999 to declaring probability = 1, is nevertheless a fallacy, and what we deduce to be very likely we should simply consider as very likely. This is true logically, but I think Newman is correct psychologically, in that there are many beliefs I hold which I cannot absolutely prove, for which I can even imagine what would constitute disconfirming evidence, but which I treat as entirely certain.
Logic and language do have their advantages and the illative sense its limitations. The former are universal and communicable. The latter is necessarily private and diverse–you either see things the way I do, or you don’t. Thus, when at last Newman addresses the arguments for religion, he confesses a degree of subjectivity. What follows is not a proof; it is what is convincing to him.
Newman divides religion into natural and revealed. Natural religion he takes to be not that of the philosophers but that studied by the anthropologists. Following that tactic that Newman uses so well of granting his opponent’s claim only to turn it against him, he takes Lucretius as his main guide for the true nature of religion. Religion is founded on the sense of sin and guilt, on fear and propitiation. The sunny religion of the philosophers is a corruption rather than a development of the primordial religious sense, founded on our experience of consciousness, that man is estranged from the gods, that the fault lies with us rather than with them, that he is personally accountable for himself and yet is sufficiently connected to his fellow creatures that one can be offered in substitution for another. A part of natural religion is the idea that the gods or God could reveal themselves to us. A mark in favor of Christianity is that it uniquely poses itself as a new revelation for all mankind, and one that addresses the deepest concerns of natural religion.
For the most part, Newman’s argument for Christianity is historical. He does not bother arguing for the historical accuracy of any reported miracles but limits himself to the broad, undisputed historical record: the history of the Jews, their expectation of a Messiah, their subsequent catastrophic turn of fortune, the remarkable growth of the Church in the face of elite disdain and persecution, and the astounding heroism of the martyrs. This will probably seem odd to a contemporary reader. Nowadays, the apologist tends to see history as an obstacle to be overcome. (“Yes, in the past all Christians were scoundrels, but their faith is true nevertheless!”) However, for most of the history of Christendom, the historical arguments were considered the strongest ones. The early Church emphasized the fulfillment of Old Testament prophesies as the decisive evidence for the Gospel. Thomas Aquinas and Dante defend belief in Christianity in almost identical terms, by pointing to the miraculous pre-Constantinian history of the Church. We should probably ask ourselves why we no longer find such arguments compelling. Given the generally more reliable intuition of past generations, perhaps we are the ones who aren’t seeing clearly.