Leon Kass on Modern Biology

"Reductionists speak loosely and not well: they mistake knowledge of the part for truth about the whole. Even if a peptide is found that, when injected into the brain, stimulates something like the sensation of falling in love, would that really be an explanation of love? Would anyone who ever loved accept, as adequate to the phenomenon, that love is (nothing but) an elevated concentration of “erotogenin” in the blood?

"Modern biology is not only materialistic but also mechanistic; indeed, it delights in nothing so much as working out “the mechanism of action” of innumerable vital phenomena. Not “what is it?” or “what is it for?” but “how does it work?” is the basic question. The mechanical model in modern biology goes back at least to Descartes. In the Discourse on Method, Descartes treats all vital activity of animals and all human activity, except for speech and will, in terms of heat and local motion: not only the life-giving motion of the heart and blood, but also wakefulness and sleep, sensing, remembering, imagining, suffering passions, and many bodily motions — all these are at bottom just different forms of local motion. And all motion, including vital motion, is understood mechanically, like the motion of a clock or automaton.

"Descartes does not say the organism is, in fact, a machine, but that we do well to consider it as a machine — for the sake of certain and useful knowledge (know-how). But is this mechanical account — or any mechanical account — sufficient, even for these limited purposes? Granted, vital processes occur in an orderly way, but does that make them fundamentally mechanical? The mechanical account leaves no room for spontaneity or self-initiated action. It ignores all inwardness of the agent: interested awareness, felt lack, appetite, intentionality and, hence, the purposiveness of lived movement — all are ignored. However useful as a heuristic concept, the mechanical account is not true to life."