Ut sol de stella: Scientific Metaphors in John Pecham’s theological Writings

This article investigates the use of scientific metaphors in the theological writings of John Pecham, demonstrating how optical, geometrical, and natural-philosophical concepts function not merely as rhetorical embellishments but as genuine hermeneutical tools. Building on the Oxford Franciscan tradition inaugurated by Robert Grosseteste and Adam of Marsh, Pecham integrates scientific knowledge into theological discourse in order to explain complex doctrines through analogies drawn from the natural world. Focusing on the principium of the Commentary on Book I of the Sentences and the Tractatus de perspectiva, the study examines three case studies: the rainbow as a metaphor for the Incarnation, the theory of vision as a model for the epistemological foundations of theology, and the symbolic association between the planets and the Virgin Mary. By comparing Pecham’s theological texts with his optical writings, the article shows that his scientific imagery is grounded in a precise understanding of contemporary optics rather than in superficial analogical reasoning. The study ultimately argues that Pecham transformed scientific theories into pedagogical and exegetical instruments, revealing the deep interdependence of natural philosophy and theology within the intellectual culture of the thirteenth-century Franciscan tradition.