According to Vico, philosophy and history had been too narrowly conceived. Philosophy had ignored the historical and empirical conditions which affect human nature, while history had ignored the metaphysical conditions. Vico therefore developed a science which would wed the two disciplines. Philosophy would provide a theory of human nature and an empirical theory about the determinate historico-sociological laws which govern human history. An "ideal external history" would be deduced from these and confirmed by its capacity to provide the systematic assumptions required for the conversion of historical evidence into historical fact. Since neither knowledge of laws nor knowledge of facts could be established independently, historico-sociological theory and historical investigation would be revealed as necessary aspects of a single epistemological enterprise.