Philosophy would render us entirely Pyrrhonian, were not nature too strong for it.

Hume makes this remark while reflecting on the practical limits of philosophical skepticism. In the first Enquiry (a revised, more accessible version of themes from his Treatise), he argues that rigorous reasoning can push us toward radical doubt about causation, the external world, and even induction. Yet human beings cannot live in a state of total suspension of belief: instinct, habit, and the pressures of ordinary life restore our confidence in everyday judgments. The line captures Hume’s characteristic balance—skeptical arguments have real force in the study, but “nature” (our psychological constitution) prevents skepticism from becoming a permanent, livable stance.

The quote means that if we followed philosophical argument alone, we would end up as thoroughgoing Pyrrhonists—suspending judgment about nearly everything. But Hume thinks our natural faculties are stronger than such abstract doubt: custom and instinct compel us to form beliefs and act, even when we cannot rationally justify those beliefs to a skeptic’s standards. The significance is that Hume relocates the foundation of much human knowledge from demonstrative proof to human nature. Skepticism is intellectually instructive and humbling, but it is also self-limiting because the mind inevitably returns to ordinary belief and practice.