David Boles: Human Meme

The provenance of this saying -- “When you hear hoofbeats behind you, don't expect to see a zebra.” -- lies in the mid-20th century. Dr. Theodore Woodward, a professor at the University of Maryland School of Medicine, used this phrase to teach medical students the principle of searching for the most common and likely diagnosis when faced with a set of symptoms, rather than jumping to rare and exotic conditions. It's a principle grounded in probability and practicality, an anchor in the turbulent seas of medical diagnosis where myriad possibilities can often cloud judgment.