Q: It occurred to me this morning that “assume” and “presume” are very close in meaning, especially when taking something to be true, and they present, at least to me, a bit of a semantic problem. Am I the only one who finds these verbs confusing?
A: No, you’re not the only one who finds them confusing. In fact, Pat has included them in a section on confusing pairs of words in her grammar and usage book Woe Is I.
Here’s the way she described them:
“ASSUME/PRESUME. They’re not identical. Assume is closer to ‘suppose,’ or ‘take for granted’; the much stronger presume is closer to ‘believe,’ ‘dare,’ or ‘take too much for granted.’ I can only assume you are joking when you presume to call yourself a plumber!
“NOTE: Presume in the sense of ‘believe’ gives us the adjective presumptive. And presume in the sense of ‘take too much for granted’ gives us the adjective presumptuous. As her favorite nephew, Bertie was Aunt Agatha’s presumptive heir. Still, it was presumptuous of him to measure her windows for new curtains.”
Now let’s exhume a few ancestors. You’re right in thinking that these words are closely connected.
Both have at their roots the Latin verb sumere (to take), so both have to do with taking something—a fact, a thing, or whatever—to oneself.
As the Oxford English Dictionary explains, “assume,” which showed up in English in the 15th century, comes from the Latin verb adsumere “to take to oneself, adopt, usurp.” Here, the Latin prefix ad- means “to.”
The older and more forceful “presume,” first recorded in the 14th century, comes from the Latin verb praesumere, in which the prefix prae- means “before.”
In classical Latin, the OED says, praesumere meant “to consume beforehand, to take upon oneself beforehand, to anticipate, to take for granted, presuppose, assume.”
Later, in post-classical Latin, the word also meant to be arrogant, to rely on, to expect, to take the liberty, to dare, and to claim.
In your question, you mention a specific use of these words—taking something to be true. Depending on the strength of your conviction, you might either “assume” or “presume” that something is true.
In this sense of the word, the OED says, “assume” means “to take for granted as the basis of argument or action,” or “to suppose.”
Here “presume” has a very similar, though stronger meaning: “to assume; to take for granted; to presuppose; to anticipate, count upon, or expect (in early use with a suggestion of overconfidence).”
And in law, according to the OED, “presume” has a specific meaning: “to take as proved in the absence of evidence to the contrary.”
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