Giambattista Vico's philosophy of history had an immense influence on 19th- and 20th-century thought. Vico replaced the premise of Cartesian epistemology with his own principle of verum factum, which states that we know the truth about matters that we have cognitively constructed. Vico's work has interesting implications for the study of the past, and yet, he uses modern scientific methods to demonstrate the potential dangers of using those methods.