All over Europe in the sixteenth century we come across public debates, disputations, altercations, dialogues and confrontations. The universities had long since tended to claim that controversial issues properly posed could be, and should be, settled by the application of the principles of logical reasoning. At Paris, Oxford, or Vienna, it was by sustaining a thesis successfully in public argument that the bachelor of arts could enter the society of masters and doctors. It was, indeed, accepted that orthodoxy must prevail, that a proposition could be philosophically sound but theologically false, any possibly heretical conclusion being disavowed beforehand. This apart, however, the superior argument prevailed, and the opponent gave way. Even in the law courts, there was in a sense the same appeal to the public argument, in so far as a jury presented its verdict on the facts put before it. Pico della Mirandola had offered to debate any one of 900 propositions with any or all comers, and it has often been pointed out that there was nothing exceptional about the presentation of Luther's ninety-five theses. Uncertainties could be resolved by reason, and reason meant the rules of logic worked out by long generations of scholastic philosophers. This could, and sometimes did, degenerate into mere verbal subtleties and argument about words from the substance of which all meaning had departed. Beyond them, however, lay the assumption that the dogmas of the church were apart and irrefutable. This could mean in practice that the Pope, the maker and interpreter of Canon Law, had the last and decisive word.