A brief tangent on 'calculus'

Jun 18, 2017

Some of you may not remember much from the calculus courses you took in high school or college.

But there are other uses for the word "calculus," and they don't involve integrals or derivatives. 

A listener named Jerry recently wrote to us with a question about one such use:

"When and how did the mathematical term 'calculus' come to refer to political thinking?"

Jerry says he often hears news reports that say something like, "That event has changed the calculus in Washington."

This was a great question for English professor Anne Curzan, who actually started off as a math major in college.

"The meaning that Jerry is referring to is older than we may realize. There are two meanings of 'calculus,' and both meanings have been in English as long as the word has been in English," Curzan said.

One of the meanings, of course, refers to the mathematical methods that involve differential and integral calculus. But there's another meaning which is just calculation or a method of calculating -- that's the meaning our listener Jerry is referring to.

Interestingly, the Oxford English Dictionary lists that second meaning as "obsolete," but modern databases contain plenty of examples like "change the calculus of a crisis" or "the moral calculus of the situation." 

"Calculus" comes into English from Latin and literally means a small stone used for counting, like the stones on an abacus. The verb form, "calculate," makes its way into English in the late 16th century, while "caculus" doesn't come in until the late 17th century.

Both words go back to the same root in Latin for different ways to talk about calculating in English.

Have you noticed any other math terms floating around in seemingly non-mathematical contexts? Let us know at rkruth@umich.edu or acurzan@umich.edu.