Empathy—understanding another's feelings—is a quality frequently demanded of us today, from charity appeals to relationships. It's a Greek term that entered English via German in the late 19th century, and literally means "feeling into," from em and pathos, meaning "in" and "feeling." Before empathy, the English word used to signal fellow-feeling was "sympathy," which comes from the Greek sym and pathos, meaning "with" and "feeling," first used in the 16th century.
The subtly different claims being made by these words reflect these periods. To be sympathetic is to feel "with" someone—a humanist updating of the more spiritually resonant 14th-century term "compassion" (from the Latin compassio, to "suffer with"). To be empathetic, however, is to feel "into" someone else—to understand as if through their eyes. It is a word with psychoanalytical associations, and reflects the growth of the medical and mental sciences at the end of the 19th century.
Nowadays, we tend to treat empathy as a special, stronger kind of sympathy—an active and commendable power of insight. "I empathise with you" is a phrase often heard during tricky personal or professional negotiations. Yet it is a word that is rarely used in its strictest sense—in which empathy is not about working out what you would feel in someone else's situation, but what they actually feel about it, however bizarre or irrational. The claim that we understand and value others' feelings is a staple of modern discourse, yet it is sometimes little more than a cover for another late 19th-century concept, "projection"—the transfer of our own desires and feelings on to those around us. Sympathy and compassion make more modest claims, but they may often be a more honest way of speaking.
