EI INCUMBIT PROBATIO QUI TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.Latin, meaning The onus of proving a fact rests upon the man. Related Posts:EI INCUMBIT PROBATIO QUI DICIT NON QUI NEGATONUSBURDEN OP PROOFACTORI INCUMBIT ONUS PROBANDIPROBATIVEQUI SENTIT COMMODUM DEBET ET SENTIRE ONUS