The National Catholic Bioethics Quarterly

Volume 22, Issue 3, Autumn 2022

Colten Maertens-Pizzo
Pages 463-475

Revisiting the Theory of Delayed Hominization

Thomas Aquinas expounded a theory of delayed hominization that has greatly influenced debates about abortion. Although many have robustly criticized this theory, its continuing appeal to supporters of abortion necessitates a reexamination. This essay will revisit Aquinas’s problematic view about the place of the rational soul in embryological development and show that he confuses the ability to reason with the capacity for reason. In a time when abortion rights debates are common and vitriolic, this essay attempts to provide clear reasons for reaffirming the moral status of the embryo from conception.