Didactic arguments are those that deduce from the principles appropriate to each subject and not from the opinions held by the answerer (for the learner must be convinced); dialectical arguments are those that deduce from reputable premisses, to the contradictory of a given thesis; examinational arguments are those that deduce from premisses which are accepted by the answerer and which any one who claims to possess knowledge of the subject is bound to know (in what manner, has been explained elsewhere); contentious arguments are those that deduce or appear to deduce to a conclusion from premisses that appear to be reputable but are not so.