Albert Schweitzer wrote that, at Chalcedon, the “doctrine of the two natures dissolved the unity of the Person, and thereby cut off the last possibility of a return to the historical Jesus.” In this article, I argue that a likely cause of this pervasive perception of Chalcedon is the reflexive deployment by modern thinkers of a Lockean concept of personhood grounded in consciousness. I argue, by way of contrast, that Thomas Aquinas’s substantial account of personhood provides greater space for historical approaches to Jesus by protecting the finite integrity of Christ’s human nature and the unity of his personhood. I conclude by highlighting an implication of this discussion for the role of metaphysics in theological reflection.