Human behavior is best explained by neuroscience in dialogue with other disciplines, not least the philosophy and theological anthropology of Thomas Aquinas. After considering neuroscience from a Thomistic perspective, this lecture frames what can be known about the human person in light of Thomism, in particular through an analysis of the four causes. The result is a greater appreciation for the advantages of interdisciplinary work in the study of the human being, who is neither a meat machine nor a visible angel.