1 Jacques Maritain, Disputed Questions, and Sexual Complementarity Some Preliminaries The friends of Maritain, all things considered, have little need to be defensive. Yet on occasion even our namesake nods. One might argue, for instance, that his effort to link evolution and embryology is suspect. Discussing the latter, he relies on a category of transformational change. But in doing so, he denies numerical identity over time. Some might counter, “so be it.” Consider, though, the words of the Psalmist. “[Y]ou created my inmost being; you knit me together in my mother’s womb” (Psalm 139: 13-14 (NIV)). Are we to substitute “you created an ordered pair of ‘virtual’ humans who preceded me”? Maritain, I submit, calls into doubt the unity of the human being. 1 It seems that he wrongly denies the formal humanity of the embryo out of loyalty to St. Thomas. 2 We do far better to employ a holistic biology together with what Nicanor Austriaco, O.P., calls a “systems hylomorphism.” On this view, which accords with common sense, a human at the embryonic stage is a human being and normally develops into one and the same human being at the adult stage. Throughout this process, one and the same soul that animates an individual substance of a rational nature. 3 Nonetheless, Maritain’s mistaken mediate hominization bespeaks the exception, not the rule. So today I come to defend our friend. Not surprisingly, some critics are hostile. Martha Nussbaum faults Maritain for a misguided and rigid deductivism in his moral reasoning. He tips his hand, she thinks, with a self-incriminating analogy. Nussbaum takes umbrage at Maritain’s proposal that just as we must retune a piano that produces discordant sounds, so must we realign ourselves with first principles and their derivations if we act discordantly. 4 Against this charge, one wants to point out that moral principles are not external, like the workings of a piano. Maritain does not suppose otherwise. Rather our lives, the lives with which the Creator blesses