The rationalistic temper may be observed in critical literature almost at the very beginning of the sixteenth century. This spirit of rationalism is observable throughout the Renaissance; and its general causes may be looked for in the liberation of the human reason by the Renaissance, in the growth of the sciences and arts, and in the reaction against mediaeval sacerdotalism and dogma. The causes of its development in literary criticism may be found not only in these but in several other influences of the period. The paganization of culture, the growth of rationalistic philosophies, with their all-pervading influence on arts and letters, and moreover the influence of Horace's _Ars Poetica_, with its ideal of "good sense," all tended to make the element of reason predominate in literature and in literary criticism. In Vida the three elements which are at the bottom of classicism, the imitation of the classics, the imitation of nature, and the authority of reason, may all be found. Reason is for him the final test of all things:-- "Semper nutu rationis eant res."[284] The function of the reason in art is, first, to serve as a standard in the choice and carrying out of the design, a bulwark against the operation of mere chance,[285] and secondly, to moderate the expression of the poet's own personality and passion, a bulwark against the morbid subjectivity which is the horror of the classical temperament.[286] It has been said of Scaliger that he was the first modern to establish in a body of doctrine the principal consequences of the sovereignty of the reason in literature.[287] That was hardly his aim, and certainly not his attainment. But he was, at all events, one of the first modern critics to affirm that there is a standard of perfection for each specific form of literature, to show that this standard may be arrived at _a priori_ through the reason, and to attempt a formulation of such standard for each literary form. "Est in omni rerum genere unum primum ac rectum ad cuius tum norman, tum rationem caetera dirigenda sunt."[288] This, the fundamental assumption of Scaliger's _Poetics_, is also one of the basic ideas of classicism. Not only is there a standard, a norm, in every species of literature, but this norm can be definitely formulated and defined by means of the reason; and it is the duty of the critic to formulate this norm, and the duty of the poet to study and follow it without deviating from the norm in any way. Even Homer, as we have seen, is to be judged according to this standard arrived at through the reason. Such a method cuts off all possibility of novelty of form or expression, and holds every poet, ancient or modern, great or small, accountable to one and the same standard of perfection.