Source : Webster's Revised Unabridged Dictionary (1913)

Probabilism \Prob"a*bil*ism\, n. [Cf. F. probabilisme.]
   The doctrine of the probabilists.

Source : WordNet®

probabilism
     n 1: a Roman Catholic system of casuistry that when expert
          opinions differ an actor can follow any solidly probable
          opinion that he wishes even though some different
          opinion might be more probable
     2: (philosophy) the doctrine that (since certainty is
        unattainable) probability is a sufficient basis for belief
        and action