Things that are definitely true or will definitely happen; facts or events about which there is no doubt.
From Latin 'certus' meaning settled or determined, through Old French 'certein' to English 'certain.' The suffix '-ty' creates the noun, and '-ties' pluralizes it to mean multiple absolute truths.
Mathematicians and philosophers have long debated what counts as certainty—even Descartes' famous 'I think, therefore I am' couldn't escape the fact that absolute certainty in science is impossible because we can always be wrong, which is why scientists prefer 'extremely high confidence' over 'certainty.'
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