I have wondered how the “success” of the spiritual life would be measured? I could imagine that the number of persons Baptized might be compared to the number of the Baptized who fall short of salvation – but there is no way to discover such a thing. In lieu of that, we often set up our own way of measuring – some expectation of “success” that we use to judge the spiritual life. “I tried Christianity…” the now self-described agnostic relates, “and found that it did not live up to its claims.”
To my mind, the entire question is a little like complaining about your hammer because it doesn’t work well as a screw-driver. The problem is that the spiritual life doesn’t “work,” and was never supposed to. It is not something that “works,” it is something that “lives.” And this is an extremely important distinction.
In 1859, Samuel Smiles, a Scottish author and government reformer, published the book, Self-Help, the first self-proclaimed work on self-improvement. His opening line is famous, “God helps those who help themselves.” Indeed, many modern people are under the impression that this statement comes from Scripture (it does not). It is not at all accidental that Smiles’ thought should echo that of the Scottish Enlightenment itself. We can build a better world, and do so more effectively by building better humans. Christianity was to be harnessed in this great progressive drive.
We look to our faith to solve problems. Whether we suffer from psychological wounds, or simple poverty and failure, we look to God for help. The spiritual life, and the “techniques” we imagine to be associated with it, are the means by which we “help ourselves” (God will do the rest).
This narrative is simply not part of the Christian faith.