David Weisman rails against the idea of a soul, in the face of neurological damage that can render a patient unable to recognize his or her own left arm and unable to know that anything is wrong:

Now consider yourself. Consider your own left arm. It feels perfect, under your control, a part of you, exactly where it should be. But this unified perception relies on neuronal machinery humming in the background, far beneath conscious awareness. Your sense of unity, only perceptible to you, is a sheen on the surface, not a deeper layer of reality.

Where does this leave the soul?

Does the soul make any sense in the face of a brain and mind so easily fractured by ischemia? A soul is immaterial, eternal, a little god, impervious to injury, able to survive our deaths. Yet here we see one injured, tethered so close to the injured brain that there is no string. We see a hole, and through it we get a glimpse into the brain’s inner workings. One part is damaged; another part falsely thinks it is whole. How does the idea of a unified soul make any sense in the face of this data?

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.