The characters in "Apology for Raymon Saybond" are philosopher's ideas from the classical period to the present. Montaigne's skepticism for the sufficiency of reason does not mean that he fully discounts its usefulness. Instead, he employs his own reason to catalog and reveal the insufficiency of belief system after belief system, school after school, and cosmology after cosmology.

His characters, then, are natural theology as an alternative to Catholicism, Protestantism, and atheism. He discusses reason as an insufficient substitute for faith, but necessary nonetheless. Man's knowledge cannot make him happy or good. Man is surpassed by animals that lack reason in many ways. Man cannot obtain knowledge (here he seems to rejects his earlier assumption of the necessity of reason). He explores and critiques Pyrrhonism, dogmatism, and classical skepticism. He rejects dogmatism and philosophical opinions. He shows skepticism toward even limited, probabilistic knowledge of academic skepticism. He then addresses epistemology and its relation to constant change and the eternal.

He concludes that changing man in a changing world can only overcome the limits of his ratiocination with divine intervention of the eternal God. This is the perennial philosophy, often called mysticism, that cosmic consciousness of the divine unity is sometimes possible.