Newman begins by asserting: “Right Reason, that is, Reason rightly exercised, leads the mind to the Catholic Faith, and plants it there, and teaches it in all its religious speculations to act under its guidance.” He explains, however, that reason does not always take the right and satisfactory path; it acts independently and often as supreme. Divine grace acts upon nature leading reason in one direction, but many times reason diverges and opposes grace. Newman notes that the religion of reason, that of the philosopher, the scholar and gentleman, while it approximates to Catholicism it can also diverge from it. Here he proposes to ascertain in outline form the principles of that religion and how it lies relative to the Catholic Faith. This religion of the philosopher does not take cognizance of the Creed. “Truths about God’s Nature, about His dealings towards the human race, about the Economy of Redemption,—in the one case it humbly accepts them, and passes on; in the other it passes them over, as matters of simple opinion, which never can be decided, and which can have no power over us to make us morally better or worse.”
Thus, discourse on religion is limited to moral duty. Newman enumerates subjects that fall under this consideration of religion: “I speak of it, for instance, as teaching the ruined state of man; his utter inability to gain Heaven by any thing he can do himself; the moral certainty of his losing his soul if left to himself; the simple absence of all rights and claims on the part of the creature in the presence of the Creator; the illimitable claims of the Creator on the service of the creature; the imperative and obligatory force of the voice of conscience; and the inconceivable evil of sensuality.” He will compare and contrast the moral, not doctrinal, teachings of Philosophy and Catholicism.
To begin the religion of the philosopher leads man to conversion from his fallen nature. It imparts upon him revulsion towards what plunges him down, but after some time the disordered passions return to pull him down. Then “sorrow, sickness, and care are providential antagonists to our inward disorders; they come upon us as years pass on, and generally produce their natural effects on us, in proportion as we are subjected to their influence.” These are the effects of natural religion on man, even though it does not raise him above nature or have the tendency to make him pleasing to God.