In Chapter 6, “Charles De Koninck, John Leslie, and the Parameters of Science,” Elizabeth Trott shows how De Koninck, a transplanted Belgium philosopher who made his career at Université Laval from 1934 onwards, and John Leslie who immigrated from Canada to England and spent the bulk of his career at the University of Guelph, both devoted their energies to delineating the limits of science with very different, though not incompatible, results. For De Koninck, this project consisted in rethinking the world in terms of the work of Einstein and other major scientists of the 20th century and examining its implications for nature and thought. De Koninck concluded that the new scientific outlook produced a “hollow universe,” both physically and mentally, where scientific research was conducted without the concept of the good. For Leslie, modern science reveals that the worlds of human experience, scientific experience, and divine causal intervention are basically the same world. Using the Platonic Forms as a necessary and eternal realm of abstract truths and the principle of ethical requiredness, Leslie argues that scientists use patterns to study the world. These patterns enable prediction and hence further discovery in science. Patterns and their recognition, however, are peculiar to the minds of persons in which case the existence of patterns requires the existence of beings who can recognize them. From the existence of beings who recognize patterns, Leslie infers the existence of a cosmic or divine mind whose thoughts give existence to the patterns. The divine mind makes comprehensible to our minds abstract and eternal Platonic truths, including the truth that the existence of a good world is undeniably more rationally convincing than the existence of an evil world. Thus, the worlds of scientific experience, human experience, and divine causal intervention are the same world and De Koninck’s “hollow universe” is filled in by a universe whose terms are related by ethical requiredness.