Can certain marvelous judicial inquiries be counted among political lots, in which the truth of guilt or innocence is permitted to be decided by a chance event? They call them vulgar purgations, and most rightly, so that the name itself indicates to us that they were introduced by no legitimate use, but by a certain usurpation of the people and by superstitious observation. Many of them are also expressly forbidden by canon law. In them God is usually tempted rather than his will explored. Hence they are called in Latin exploratory trials; but by a barbarous word in the Neapolitan Constitutions they are called paribiles leges, because they make the thing not known but merely apparent. It will be proved afterward that in these practices there is usually sin by tempting God.
Such a purgation occurs whenever it is asked that God perform a miracle: for example, if someone, trusting in his innocence, should ask to be struck seven times with a sword in order to prove his innocence, as happened in the case of a woman struck seven times, or should enter fire, about which later.
[margin: Canon-law references against vulgar purgations include chapter dilecti, De purgatione canonica, and chapter tribus, De consecratione, distinction 2; the Neapolitan Constitutions and the term paribiles leges; Jerome’s letter concerning the woman struck seven times]