probabilism n.

late 14c., "likely, reasonable, plausible, having more evidence for than against," from Old French probable "provable, demonstrable" (14c.), from Latin probabilis "worthy of approval, pleasing, agreeable, acceptable; provable, that may be assumed to be believed, credible," from probare "to try, to test" (see prove). As a legal term, probable cause "reasonable cause or grounds" is attested from 1670s.

Probable cause (used with reference to criminal prosecutions), such a state of facts and circumstances as would lead a man of ordinary caution and prudence, acting conscientiously, impartially, reasonably, and without prejudice, upon the facts within his knowledge, to believe that the person accused is guilty. [Century Dictionary]

Related: Probableness.

word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.

1855, in Catholic theology (see probabilism), from probabilist "one who holds the doctrine of probabilism" (1650s, from French probabiliste, 17c., from Latin probabilis, see probable) + -ic. Meaning "pertaining to probability, involving chance variations" is from 1951.