Thierry of Chartres and Gundissalinus on Spiritual Substances: The Problem of Hylomorphic Composition

In this essay, the author examines the problem of the composition of spiritual substances in Thierry of Chartres and Gundissalinus. While Thierry is reticent to admit a hylomorphism in spiritual creatures, Gundissalinus develops Thierry’s thought on the matter through al-Ghazālī’s and Ibn Daud’s treatment of the composition in spiritual substances. Gundissalinus concludes that spiritual creatures are composed of matter and form (if not exactly in the way that Ibn Gabirol proposes), a conclusion that would be unacceptable to his main philosophical authorities.