This article argues against theistic evolution by outlining key tenets of Thomistic philosophy regarding creation. The author emphasizes the Church's consistent teaching that God alone creates directly from nothing (ex nihilo), a concept elaborated upon by St. Thomas Aquinas. Haigh explains Thomistic ideas such as the distinction between God's absolute being and the derived existence of creatures, the nature of creation as an immediate act rather than a process, and the limitations inherent in created essences, concluding that these principles fundamentally contradict the notion of evolution, theistic or otherwise, by suggesting it improperly attributes creative power to secondary causes and natural processes.