On De Anima or On the Soul (350 BCE), books 1 and 2, after some listener mail. What can this ancient text tell us about biological life? What counts as a scientific explanation? A. describes life as "the first actuality of a natural body which has organs," so bodies express their nature only when they're growing and reproducing and all that stuff that bodies do. The body is potential, and life is its actuality. So what the heck kind of explanation is that, and how does it tie into Aristotle's convoluted metaphysics?

End song: "Intermission Song" by Mark Lint from Spanish Armada: Songs of Love and Related Neuroses (1993).