"If religion is faith in things unprovable, then not only is mathematics a religion, but (vis-à-vis Gödel's Second Incompleteness Theorem) it is also the only religion that can prove itself to be a religion."
–– HT to Albert in the thread for this post by Mark Shea.
It's also worth reproducing the quotation from the Prophet Gilbert:
Spiritual doctrines do not actually limit the mind as do materialistic denials. Even if I believe in immortality I need not think about it. But if I disbelieve in immortality I must not think about it. In the first case the road is open and I can go as far as I like; in the second the road is shut. But the case is even stronger, and the parallel with madness is yet more strange. For it was our case against the exhaustive and logical theory of the lunatic that, right or wrong, it gradually destroyed his humanity. Now it is the charge against the main deductions of the materialist that, right or wrong, they gradually destroy his humanity; I do not mean only kindness, I mean hope, courage, poetry, initiative, all that is human. For instance, when materialism leads men to complete fatalism (as it generally does), it is quite idle to pretend that it is in any sense a liberating force. It is absurd to say that you are especially advancing freedom when you only use free thought to destroy free will. The determinists come to bind, not to loose. They may well call their law the “chain” of causation. It is the worst chain that ever fettered a human being. You may use the language of liberty, if you like, about materialistic teaching, but it is obvious that this is just as inapplicable to it as a whole as the same language when applied to a man locked up in a mad-house. You may say, if you like, that the man is free to think himself a poached egg. But it is surely a more massive and important fact that if he is a poached egg he is not free to eat, drink, sleep, walk, or smoke a cigarette. Similarly you may say, if you like, that the bold determinist speculator is free to disbelieve in the reality of the will. But it is a much more massive and important fact that he is not free to raise, to curse, to thank, to justify, to urge, to punish, to resist temptations, to incite mobs, to make New Year resolutions, to pardon sinners, to rebuke tyrants, or even to say “thank you” for the mustard.
In passing from this subject I may note that there is a queer fallacy to the effect that materialistic fatalism is in some way favourable to mercy, to the abolition of cruel punishments or punishments of any kind. This is startlingly the reverse of the truth. It is quite tenable that the doctrine of necessity makes no difference at all; that it leaves the flogger flogging and the kind friend exhorting as before. But obviously if it stops either of them it stops the kind exhortation. That the sins are inevitable does not prevent punishment; if it prevents anything it prevents persuasion. Determinism is quite as likely to lead to cruelty as it is certain to lead to cowardice. Determinism is not inconsistent with the cruel treatment of criminals. What it is (perhaps) inconsistent with is the generous treatment of criminals; with any appeal to their better feelings or encouragement in their moral struggle. The determinist does not believe in appealing to the will, but he does believe in changing the environment. He must not say to the sinner, “Go and sin no more,” because the sinner cannot help it. But he can put him in boiling oil; for boiling oil is an environment.
–– Orthodoxy, ch. 2.