 In the work, Vico consciously develops his notion of scienza (science or knowledge) in opposition to the then dominant philosophy of Descartes with its emphasis on clear and distinct ideas, the most simple elements of thought from which all knowledge, the Cartesians held, could be derived a priori by way of deductive rules. As Vico had already argued, one consequence and drawback of this hypothetico-deductive method is that it renders phenomena which cannot be expressed logically or mathematically as illusions of one sort or another. This applies not only most obviously to the data of sense and psychological experience, but also to the non-quantifiable evidence that makes up the human sciences. Drawing on the verum factum principle first described in De Antiquissima, Vico argues against Cartesian philosophy that full knowledge of any thing involves discovering how it came to be what it is as a product of human action and the “principal property” of human beings, viz., “of being social” (“Idea of the Work,” §2,  p.3).[7]  The reduction of all facts to the ostensibly paradigmatic form of mathematical knowledge is a form of “conceit,” Vico maintains, which arises from the fact that “man makes himself the measure of all things” (Element I, §120, p.60) and that “whenever men can form no idea of distant and unknown things, they judge them by what is familiar and at hand” (Element II, §122, p.60). Recognizing this limitation, Vico argues, is at once to grasp that phenomena can only be known via their origins, or per caussas (through causes). For “Doctrines must take their beginning from that of the matters of which they treat” (Element CVI, §314, p.92), he says, and it is one “great labor of...Science to recover...[the] grounds of truth-truth which, with the passage of years and the changes in language and customs, has come down to us enveloped in falsehood” (Element XVI, §150, pp.64–5). Unveiling this falsehood leads to “wisdom,” which is “nothing but the science of making such use of things as their nature dictates” (Element CXIV, §326, p.94). Given that verum ipsum factum-“the true is the made,” or something is true because it is made-scienzia both sets knowledge per caussas as its task and as the method for attaining it; or, expressed in other terms, the content of scienza is identical with the development of that scienza itself.