From H. L. Mencken's obituary for J. Gresham Machen, the proto-evangelical:

There was a time, two or three centuries ago, when the overwhelming majority of educated men were believers, but that is apparently true no longer. Indeed, it is my impression that at least two-thirds of them are now frank skeptics. But it is one thing to reject religion altogether, and quite another thing to try to save it by pumping out of it all its essential substance, leaving it in the equivocal position of a sort of pseudo-science, comparable to graphology, "education," or osteopathy. 

That, it seems to me, is what the Modernists have done, no doubt with the best intentions in the world. They have tried to get rid of all the logical difficulties of religion, and yet preserve a generally pious cast of mind. It is a vain enterprise. What they have left, once they have achieved their imprudent scavenging, is hardly more than a row of hollow platitudes, as empty as [of] psychological force and effect as so many nursery rhymes. They may be good people and they may even be contented and happy, but they are no more religious than Dr. Einstein. Religion is something else again — in Henrik Ibsen's phrase, something far more deep-down-diving and mudupbringing, Dr. Machen tried to impress that obvious fact upon his fellow adherents of the Geneva Mohammed. He failed — but he was undoubtedly right. 

This has always struck me as the proper view of the matter. I could be Machenesque or I could be Menckenesque, but I could never be a theological Modernist. 

The first person to demonstrate this to me was Nietzsche, in his great early essay “David Strauss, the Confessor and the Writer,” in Untimely Meditations. Nietzsche’s scorn for Strauss’s attempt to build a post-Christian religion on the foundation of Darwinism is eviscerating. Nietzsche shows that the Darwinian model of the cosmos is not exactly a consoling one — and yet Strauss wants to console, wants to be a kind of optimist. So: 

Whereupon Strauss started the ‘soothing oil’ flowing, led on a God who errs out of a passion for error, and assumed for once the wholly uncongenial role of a metaphysical architect. He does all this because his ‘we’ are afraid and he himself is afraid – and here we discover the limits of his courage, even with respect to his ‘we’. For he does not dare to tell them honestly: I have liberated you from a helpful and merciful God, the universe is only a rigid machine, take care you are not mangled in its wheels! This he dares not do: so he has to call in the sorceress, that is to say metaphysics. 

A metaphysics meant, essentially, to make his readers believe that the “rigid machine” of the cosmos is a kind of worship-worthy God, or at least the secure grounding of a new religion. 

At bottom, then, the new religion is not a new faith but precisely on a par with modern science and thus not religion at all. If Strauss nevertheless asserts that he does have a religion, the reasons for it lie outside the domain of contemporary science. Only a minute portion of Strauss’s book, amounting to no more than a few scattered pages, treats of that which Strauss could have a right to call a faith: namely that feeling for the cosmos for which he demands the same piety as the believer of the old stamp feels towards his God. In these pages at least the scientific spirit is certainly not in evidence: but we could wish for a little more strength and naturalness of faith! For what is so extremely striking is the artificiality of the procedures our author has to adopt in order to convince himself he still possesses a faith and a religion at all: as we have seen, he has to resort to jabbing and cudgelling. It creeps weakly along, this stimulated faith: we freeze at the sight of it. 

Nietzsche has a usefully clarifying effect on those of us who want to see what our actual choices are. Mencken was pretty good at that also.