'Nous alone enters from outside' Aristotelian embryology and early Christian philosophy

In a work entitled On the Generation of Animals, Aristotle remarks that “intellect (nous) alone enters from outside (thurathen)”. Interpretations of this passage as dualistic dominate the history of ideas and allow for a joining together of Platonic and Aristotelian doctrine on the soul. This, however, pulls against the well-known Aristotelian position that soul and body are intertwined and interdependent. The most influential interpretations thereby misrepresent Aristotle’s view on soul and lack any real engagement with his embryology. This paper seeks to extract the account of intellect (nous) in Aristotelian embryology from this interpretative background and place it within the context of his mature biological thought. A clear account of the actual import of this statement in its relevant context is given before explaining how it has been misunderstood by various interpretative traditions. The paper finishes by touching on how early commentary by Christian writers, freed as it was from the imperative to synthesise Greek philosophy, differed from those that came after. While realising that Aristotle’s position would not aid them in their explanations of the soul’s survival after death, their engagement with Aristotle’s science allowed for other aspects of theology concerning the fittingness of soul to body.