Karl Popper originally spoke of how we might determine the degree to which a theory was ‘confirmed’. This led to misunderstandings of his epistemology where philosophers in the Vienna circle thought he believed it possible to determine a theory was “more certain” or at least “more probable.” So he started to instead use the term “corroborate” instead of “confirm” because it had less philosophical baggage among the Vienna circle. (Logic of Scientific Discovery, p. 249, footnote)
But have you ever looked up these terms in a dictionary? Let’s do so right now:
- to establish the truth, accuracy, validity, or genuineness of; corroborate; verify: This report confirms my suspicions.
- to acknowledge with definite assurance: Did the hotel confirm our room reservation?
- to make valid or binding by some formal or legal act; sanction; ratify: to confirm a treaty; to confirm her appointment to the Supreme Court.
- to make firm or more firm; add strength to; settle or establish firmly: Their support confirmed my determination to run for mayor.
- to strengthen (a person) in habit, resolution, opinion, etc.: The accident confirmed him in his fear of driving.
- to make more certain; confirm: He corroborated my account of the accident.
This is just the first definition I could find for each. I didn’t look up multiple dictionaries. At least for dictionary.com, each word references the other as its definition! So they are actually synonyms! (Well, at least for those not in the Vienna Circle.)
I conjecture that some Popperian will now say that the dictionary is wrong.