"the irreconcilable duality of body and soul, that fundamental human experience"

Descartes drawing of mind-body dualism
Public DomainDescartes drawing of mind-body dualism
The narrator refers to the long-standing philosophical and theological problem of the apparent division between mind and body, soul and flesh, consciousness and matter, which is at the heart of everything from religious faith and its assertion of an afterlife, to the philosophy of René Descartes (who turns up much later in the book during the discussion of the treatment of animals; see Bookmark for page 288).

The drawing at left is by Descartes, from his "Metaphysical Meditations," showing the function of the pineal gland, and thereby illustrating the mind-body dualism.

Discussion of a mind-body split, or an incorporeal entity known as a “soul,” goes back at least as far as Zarathustra, Plato, and Aristotle, but Descartes’ writings are probably the most famous on the subject.

The narrator says that modern medical science has done away with much of our knee-jerk concerns about mind vs. body -- the soul is simply electrochemical impulses in grey matter and muscular motions of the heart -- but the rumbling demands of the stomach can tear us away from passionate love in a way that reminds us of that split between mind and body all over again.