The brain is one troubling organ. The gateway to both our thinking and our physical experience—as well as our survival—it tends to explain things in terms of narrative. Human consciousness likes a good story. Experiment after experiment has shown that if the brain doesn’t know why you do something it will make up an answer. Consciousness is far from foolproof. Those who rely too heavily on rationalism don’t like to think about such things. Logically, if your brain can fool you then you can’t believe everything evidence seems to verify. Think about that. If you dare.

Psychology has sometimes received a bad rap among the sciences for not having empirical evidence to back up some of its assertions. “Freudian” is now used as much as a slur as it is a sign of the sudden insight that strange things constantly go on inside our heads. BBC Future recently ran a story by Melissa Hogenboom titled, “The woman whose tumour made her religion deadly.” The account regards a woman who came to the hospital with serious self-inflicted wounds. Although hackneyed, the voices in her head told her to do this to herself. Brain scans indicated a tumor at the point in her brain where auditory information and religious belief come together. Paging Dr. Jaynes! Now, I know this is over-simplified. I’ve read enough neurology to know that brain functions can switch from one part of the brain to another and that mapping this kilo-and-a-half universe is one of the the most vexing of scientific enterprises. Still, in this case, the implications were clear: the woman’s self-destructive behavior was connected, in her brain, to religious commands.

Many educated people in this post-Christian world rely staunchly on reason. I don’t disagree that reason is essential. I do wonder, however, what happens when such thinking is forced to confront the fact of the irrational brain. Ever since setting our clocks forward I’ve been awaking in the midst of dreams. My usual sleep cycle hasn’t yet adjusted. I know some pretty strange stuff is going on in my brain when rationality’s taking a snooze. The other day I awoke convinced I was in my boyhood home. Rationality tells me it was razed years ago. Yet this brain with doctoral-level education was convinced it was in another state at another time. And this isn’t the result of a tumor, but normal sleeping brain functioning. It does make one wonder if putting too much faith into rationality isn’t a form of minor neurosis. To find out you have to ask a troubling organ and hope for a rational answer.