Blind as a mole

Origin

Deep beneath the soil, the common mole leads a life largely independent of sight. Though they possess tiny eyes, sometimes no bigger than a pinhead and often obscured by thick fur or even skin, their vision is incredibly poor, primarily serving to detect light or darkness. It was this remarkable adaptation to a subterranean existence—their tireless burrowing, guided by an acute sense of smell and touch rather than sight—that captured the human imagination. Long before scientific understanding of their biology, ancient observers noted the mole's apparent blindness, making it a perfect, vivid metaphor for anyone utterly incapable of seeing, whether literally or figuratively. The phrase thus became firmly rooted in English, a testament to the creature's unique, sightless world.