LOSING FAITH IN GOD in the 21st century is an anachronistic experience. You end up contending with the kinds of things the West dealt with more than a hundred years ago: materialism, the end of history, the death of the soul. During the early years of my faithlessness, I read a lot of existentialist novels, filling their margins with empathetic exclamation points. “It seems to me sometimes that I do not really exist, but I merely imagine I exist,” muses the protagonist of André Gide’s The Counterfeiters. “The thing that I have the greatest difficulty in believing in, is my own reality.” When I think back on that period of my life, what I recall most viscerally is an unnamable sense of dread — an anxiety that would appear without warning and expressed itself most frequently on the landscape of my body. There were days I woke in a panic, certain that I’d lost some essential part of myself in the fume of a blackout, and would work my fingers across my nose, my lips, my eyebrows, and my ears until I assured myself that everything was intact. My body had become strange to me; it seemed insubstantial. I went out of my way to avoid subway grates because I believed I could slip through them. One morning, on the train home from work, I became convinced that my flesh was melting into the seat.

At the time, I would have insisted that my rituals of self-abuse — drinking, pills, the impulse to put my body in danger in ways I now know were deliberate — were merely efforts to escape; that I was contending, however clumsily, with the overwhelming despair at the absence of God. But at least one piece of that despair came from the knowledge that my body was no longer a sacred vessel; that it was not a temple of the holy spirit, formed in the image of God and intended to carry me into eternity; that my body was matter, and any harm I did to it was only aiding the unstoppable process of entropy for which it was destined. To confront this reality after believing otherwise is to experience perhaps the deepest sense of loss we are capable of as humans. It’s not just about coming to terms with the fact that you will die. It has something to do with suspecting there is no difference between your human flesh and the plastic seat of the train. It has to do with the inability to watch your reflection appear and vanish in a window without coming to believe you are identical with it.