This doctrine, superior as it is to the allegorical and historical theories, is another aspect of Vico's vindication of the non-logical forms of knowledge as against the intellectualism which denied them and merely represented them either as artificial forms or as due to supernatural causes. Nor does the opinion seem acceptable which attaches Vico to the Neo-Euhemeristic school. He does not indeed explicitly combat this school, and we may even grant that he presents certain superficial resemblances to it: but together with the resemblances there is this radical difference, that for Vico the stories are not alterations of actual history, but are essentially history; their supposed alteration is the actual truth as it appeared to the primitive mind. Vico did not and could not give a more precise determination of the nature of myth, precisely because owing to the fluctuating character of his concept of poetry, itself he was not in a position to lay down the boundary between the two forms. He talks generally of poetry and myth as distinct things, but he does not establish the distinction. And yet Vico was familiar enough with the concept which supplies this distinctive criterion, and had enunciated it: but instead of using it for his doctrine of mythology, he had made of it one or more of his various definitions of poetry. That "poetic character," that "imaginative universal" whose introduction into aesthetic as the explanatory principle of poetry causes so many insuperable difficulties, is really the definition of mythology, and as such provides the science of mythology with the true principle that is required. If the concept of accomplishing great labours for the common welfare cannot be disengaged from the idea of a particular man who accomplished one of these labours, this concept becomes for instance the myth of Hercules: and Hercules is at once an individual man who does individual actions, and kills the Lernaean hydra and the Nemean lion or cleanses the stables of Augeas, and also a concept: just as the concept of beneficent and glorious labour is at once a concept and Hercules: a universal and an imaginary idea: an imaginative universal.