Institutio Oratoria

the folly

shown in their commission is out of all proportion to the skill required to deal with them: I refer to mistakes such as advancing a disputable argument as indisputable, a controversial point as admitted, a point common to a number of cases as peculiar to the case in hand, or the employment of trite, superfluous, or incredible arguments. For careless speakers are liable to commit a host of errors: they will exaggerate a charge which has still got to be proved, will argue about an act when the question is who committed it, will attempt impossibilities, drop an argument as if it were complete, whereas it is scarcely begun, speak of the individual in preference to the case,