Volume 26, Issue 1, Spring 2021
The Metaphysical Problem for Theistic Evolution
Accidental Change Does Not Generate Substantial Change
This paper focuses on one of the metaphysical problems facing theistic conceptions of evolution: namely, that of evolutionary transition from one specified substantial form to another. According to the evolutionary account, new substantial forms appear due to accidental changes in previously existing substances. However, accidental change may only lead to the production of new accidents, not entirely new and distinct substantial forms. The solutions proposed by modern Thomists go in two directions: reducing the number of substantial forms (species), and rejecting substantial form altogether. Both proposals deviate from classical metaphysics. The evolutionary account of the origin of species is ultimately obliged to challenge the real existence of species, and so leads to nominalism. As such it cannot be reconciled with classical metaphysics.