When Thomas Aquinas was writing his summa theologiae, the zombie apocalypse was considered too far in the future to be of direct relevance to the teaching of theology. Happily, modern writers have addressed this sad lacuna in the summa. However, less noticed is the fact that Aquinas did in fact talk about zombies without actually naming them as such. Where do we find this teaching?
The York Aquinas Reading Group has turned its attention to the Angels. In Ia.q51, Aquinas considers the bodily appearences of angels to men spoken about in the scriptures. It appears that the angels are using human bodies in some way or another. What is the nature of the relationship between angel and human body? In this short question Aquinas immediately discounts (article 1) the idea that the angels (as pure form) are united to the body as form is united to matter. But it is clear that the angels in some way assume human bodies (Article 2). What is the state of such a human body when it is under the power of an angel? In article 3, Aquinas denies that the human body assumed by the angel is alive; moreover the angel itself is not exercising vital functions through this body.
What Aquinas appears to have in mind here is something akin to the notion of zombie in modern philosophy of mind. In this context a zombie is a hypothetical exact physical copy of a human being but which has no consciousness, qualia or sentience. So, did Aquinas arrive at the modern notion of a zombie many centuries before they arose in the philosophy of mind?