Life Is Like Riding A Bicycle

Einstein wrote this in a letter to his son Eduard on February 5, 1930 (Einstein Archives 75-990). The original German — "Beim Menschen ist es wie beim Velo. Nur wenn er faehrt, kann er bequem die Balance halten" — translates more literally as "It is the same with people as it is with riding a bike. Only when moving can one comfortably maintain one's balance." The popular English version is a paraphrase, but the underlying sentiment is faithfully preserved. The letter was first brought to wide attention by Walter Isaacson in his 2007 biography Einstein: His Life and Universe.