|1.||philosophy the doctrine that although certainty is impossible, probability is a sufficient basis for belief and action|
|2.||the principle of Roman Catholic moral theology that in a situation in which authorities differ as to what is the right course of action it is permissible to follow any course which has the support of some authority|
in casuistry, a principle of action grounded on the premise that, when one does not know whether an action would be sinful or permissible, he may rely on a "probable opinion" for its permissibility even though a more probable opinion calls it sinful. An opinion is considered probable either if sound, logical arguments can be cited in its favour (intrinsic probability) or if recognized authorities give it support (extrinsic probability).
Learn more about probabilism with a free trial on Britannica.com.