A hallmark of Western civilization is reasoned inquiry in pursuit of permanent knowledge (truth), Gregg writes in the Thomist tradition. Unaided reason degenerates into mere empiricism, sidelining the benefits of Christian logos while engendering pathologies such as social engineering, scientism, nihilistic skepticism, and relativism (i.e., reason reaching non-empirical truths).

Reason is not equivalent to the scientific method, for the premises of an argument may be self-evident: deductive reason follows a logical path. Judaism had separated human reason from mythology, and St. Paul is a key source of natural law, that which all men can discern (regardless of religion); however, Christian religion is not based on Mosaic law but first-hand witness of the miraculous – the resurrection is a historical event. Christianity’s contribution to rationality originates in God’s rational nature (logos).

Epistemological arguments, including the empiricism of Locke, encourage a view of religion as superstition and further that men are entirely shapeable (tabula rasa). This gave rise tot Prometheanism, but Western institution often reflect the truths of unchanging human nature. Islamic belief that only God establishes truth is despotic: the people cannot reason but only follow interpretation.