SYSTEMS OF PROBABILITY
Theories about the degree of doubt or probability that will exempt a person from the obligation of a doubtful law. Five systems have been developed (of which the first and last are more speculative than practical), namely tutiorism, probabiliorism, equiprobabilism, probabilism, and laxism. According to tutiorism, a person must be certain or nearly certain (tutior, safer) that the doubtful law does not bind; and laxism holds that even a thinly or dubiously probable reason in favor of liberty exempts one from observing a doubtful law. Probabiliorism says that the evidence against a dubious law must be more probable than the opposite. Equiprobabilism claims that the evidence must be as probable as the opposite. Probabilism holds that any solidly probable argument against the existence or application of a doubtful law is enough to keep it from binding.