History is loaded with coincidences. For instance, did you know that John Adams and Thomas Jefferson died within hours of each other, on July 4, 1826? That just happened to be the 50th anniversary of the signing of the Declaration of Independence, which Adams and Jefferson both helped draft.
Though the timing is curious, Adams' and Jefferson's deaths were merely a coincidence, or concurrent events that have no apparent causal connection. It's that lack of connection that sparked a question from listener Erik Kuszynski.
Kuszynski asks, "If I wanted to say that two related events happened at the same time, I might say 'Those two things coincide with each other,' but I wouldn’t say 'Those two things are coincidental.' Where did this implication of unrelatedness come from?"
"Coincidence" had a couple of different meanings when it first came into English from French in the early 1600s, neither of which included the "unrelatedness" implication. It could mean "the occupation of the same place" or "simultaneous occurrence or existence," i.e., two things happening at the same time.
By the late 1600s "coincidence" had picked up the meaning "happening at the same time with no apparent causal connection," and that's how most of us use it today.
Though the earlier meaning of "two things happening at the same time" is no longer very common for "coincidental" or "coincidence," it does pop up from time to time such as "coincidental penalties" in sports.
Merriam-Webster dictionaries list this older meaning as "formal." That's actually a bit of a coincidence, since "coincidence" first came into English as a rather formal, scholarly word, often used in mathematics and philosophy. However, it became more and more popular.
Philologist George Perkins Marsh had a theory about this usage increase. In the mid-1800s, he noted that when Thomas Jefferson and John Adams both died on the 50th anniversary of the Declaration of Independence, many people described it as an "extraordinary coincidence." Marsh theorized that everyone describing the deaths this way helped "coincidence" become a much more widely used word.
Sadly, that's probably not true.
"Now that we can go into Google Books and look at usage, it turns out that 'coincidence' was gaining in popularity before Jefferson and Adams died," says Professor Anne Curzan. "It was probably that popularity that caused it to be used to describe Jefferson and Adams dying on the same day."
To hear more about "coincidence," including one use that really gets under linguists' skin, listen to the audio above.
