In the last part of this chapter, St. Thomas presents two cosmological arguments about the impossibility of an endless cycle of life and death for human beings.
Contemporary cosmologists would no doubt consider St. Thomas’ scientific ideas quaint. But I think he actually achieves a more-profound insight.
St. Thomas includes the perceiving mind within his overall conception of the cosmos. The mind or soul, which can know and understand, exists as a greater being than any material thing in motion, including the earth, sun, and moon–whose motions relative to each other give rise to our conception of time passing.