To reject gods and spirits is easy: just bully them away in the name of science.
But to accept them, or at least our experiences of them, and yet give them a scientific explanation: there's a task worthy of our art. It demands that we look them in the eye and take them seriously, while standing absolutely firm in our materialist convictions.
I don't know how much of what I'm about to say is true. All I know is that it's damn interesting.