After that everything lies in the investigation as to whether a thesis conforms mediately or immediately to the principles one is agreed upon' (which is done by means of the syllogisms of him who makes objections); 'whether the premisses of a proof (advanced by the opposer) 'are true; whether the conclusion is properly drawn; whether a four term Syllogism has been employed; whether some aphorism of the chapter de oppositis or de sophisticis elenchis etc., has not been violated.'