 Mill divided the broad category of argument fallacies into two groups: those in which the evidence is distinctly conceived and those in which it is indistinctly conceived. Fallacies falling under evidence indistinctly conceived (Bk. V, vii) were further described as fallacies of confusion. These result from an indistinct conception of the evidence leading to a mistaking of its significance and thereby to an unsupported conclusion. Some of the traditional Aristotelian fallacies such as ambiguity, composition and division, petitio principii, and ignoratio elenchi, are placed in this category. Although Mill followed Whately closely in his exposition of the fallacies of confusion, he does not mention any ad-arguments in connection with ignoratio elenchi.