There were never in the world two opinions alike, any more than two hairs or two grains. Their most universal quality is diversity.

Montaigne (1533–1592) developed his skeptical, exploratory style in the Essays amid the French Wars of Religion, a period marked by violent sectarian certainty and competing dogmas. Writing largely in retirement at his tower library in the 1570s–1580s, he repeatedly stresses the variability of human judgment, custom, and temperament. The line is characteristic of his habit of countering claims of universal agreement with observations drawn from everyday experience and from classical authors: people differ not only in beliefs but in the very ways they perceive and reason. In English it commonly appears in translations of the Essays as part of his reflections on the endless variety of opinions.

The remark argues that diversity is not an exception but the defining feature of human thought. By comparing opinions to hairs or grains—objects that seem interchangeable at a glance yet are never identical—Montaigne undercuts the expectation that rational inquiry will yield uniform conclusions for everyone. The point supports his broader skepticism: because minds, experiences, and customs differ, certainty and consensus are fragile, and humility is warranted in moral and religious disputes. At the same time, the line can be read as a defense of pluralism: disagreement is natural, so tolerance and curiosity are more reasonable responses than coercion or dogmatic insistence.