Probabilism is the moral system according to which in a doubt of conscience about the morality of a particular course of conduct, a person may lawfully follow the opinion for liberty, provided it is truly probable, even though the opinion for law is definitely more probable. The defenders of this system apply their fundamental principle: "A doubtful law does not bind" (Lex dubia non obligat ) to both divine and human laws, whether the doubt concerns the existence or the cessation of the law. However, they admit the exceptions to the use of reflex principles. Moreover, they require a person reasonably to seek direct certainty regarding the moral problem before seeking indirect certainty through the use of reflex principles. The outstanding exponents of this system emphasize that the opinion for liberty must be truly and solidly probable, for if it is only slightly probable it has no value against the opinion for law. Thus, probabilism is clearly distinguished from laxism. Jesuit theologians are the best known exponents of probabilism.
See Also: morality, systems of; conscience; reflex principles; doubt, moral; laxism.
Bibliography: d. m. prÜmmer, Manuale theologiae moralis, ed. e. m. mÜnch, 3 v. (10th ed. Barcelona 1945–46) 1:342. j. aertnys and c. a. damen, Theologia moralis, 2 v. (16th ed. Turin 1950) 1:101. m. zalba, Theologiae moralis compendium, 2 v. (Madrid 1958) 1:679–703. j. m. harty, The Catholic Encyclopedia, ed. c.g. herbermann et al., 16 v. (New York 1907–14; suppl. 1922) 12:441–446. t. deman, Dictionnaire de théologie catholique, ed. a. vacant et al., 15 v. (Paris 1903–50; Tables générales 1951–) 13.1:417–619.
[f. j. connell]