I was struck by how different death is from sleep. A sleeping individual shimmers with fractional movements. The dead seem to rest in paused animation, so still they look smaller than in life. It’s almost impossible not to feel as if something very like the soul is no longer present.
Descartes argued that thought is so different from the physical, machine-like substance of the body that we should see humans as having two parts: the thoughtful mind and the thoughtless, physical body. This was religion refocused through a rational lens. The division between humans and the rest of nature was no longer the soul – or, at least, not only the soul – but rather our intellectual capabilities: our reason, our moral sensibilities, our gifts for abstraction. He assumed, of course, that other animals don’t think.