As geographers, Sosius, crowd into the edges of their maps parts of the world which they do not know about, adding notes in the margin to the effect that beyond this lies nothing but sandy deserts full of wild beasts, and unapproachable bogs.

Plutarch uses the image of ancient mapmakers who fill unknown regions with speculative warnings to criticize a common intellectual habit: when knowledge runs out, people often substitute conjecture, fear, or rhetorical invention. The address to “Sosius” suggests a conversational, epistolary setting, and the metaphor implies that the margins of inquiry tempt writers to assert confident-sounding claims about what lies “beyond,” even when they have no evidence. The point is not about geography per se but about epistemic humility—recognizing the limits of what can be responsibly said—and about the dangers of letting imagination or prejudice masquerade as fact at the boundaries of understanding.