 Mill drew a division between the moral and the intellectual causes of fallacies. The former are aspects of human nature such as biases and indifference to truth which incline us to make intellectual mistakes. These dispositions are not themselves fallacies. It is the intellectual errors, the actual taking of insufficient evidence as sufficient, that are fallacious. The various ways in which this can happen are what Mill took as the basis for classifying fallacies. “A catalogue of the varieties of evidence which are not real evidence,” he wrote, “is an enumeration of fallacies” (1891, Bk.V iii §1).