In Vico's viewpoint, Cartesian thinking method is based on segregation and analysis of concepts, and the ultimate aim of this method is gaining certainty. The certainty is merely achievable in the frame of clearance and distinctness. For Descartes, it is impossible to achieve clearance and distinctness in historical and cultural studies, thus there is no place for such branches of knowledge in his method. According to Vico, Cartesian reason is devoided from its past, history and society. In his view, the crucial fault of Cartesian reason is its neglect of the role of faculty of imagination in the process of historical development of reason. Vico introduces a kind of thinking method among the ancients, which he calls poetic wisdom. In this method, reason with the aid of imagination, instead of segregation, analysis and criticism, attempts to find and make relation between different issues and domains that finally leads to new horizons. Poetic wisdom does not make human devoided from nature, history and society, rather it seeks synthesis and unity.