As his (C. S. Lewis’s) good friend Owen Barfield once remarked, Lewis radiated a sense that the spiritual world is home, that we are always coming back to a place we have never yet reached.

Though there are exceptions, Hinduism, Buddhism, and Taoism tend to stress desirable states of consciousness, escaping the fretful, self-aware state of mind that so often makes everyday living a burden. For mystics from the Abrahamic...