  Kurt Flasch attempts to put Dietrich’s contributions to the philosophy of mind in its proper perspective. To see what Dietrich has accomplished we must try to understand how he introduces a new element into medieval scholastic speculations concerning mind. To begin with, Flasch notes, Dietrich’s distinction between ens reale and ens conceptionale replaces the old scholastic distinction between ens naturae and ens rationis in such a way that it is no longer possible to claim that being as found in the mind is dependent upon extra-mental reality. Where Thomas Aquinas claimed an exclusive distinction between the two categories of being, Dietrich with his doctrine of coextentionality insists on an inclusive distinction. The result of this new perspective on the priority of ens conceptionale, Flasch argues, not only grounds a new metaphysics but also establishes a new methodology for studying nature based upon an inclusive understanding of natural being. Looked at in this way Dietrich’s theory of mind can indeed be seen as the culmination of his philosophy.