 After completing his dissertation, on the doctrine of chance, under Lotze in 1870, Windelband (1848–1915), moved to Strassburg in 1882, and then to Heidelberg in 1902. A master essayist, he is best known for the essays and addresses collected in his Präludien (1915), which was first published in 1883. In “Critical or Genetic Method?”—the important essay just mentioned—Windelband self-consciously looks to Kant and the critical philosophy as the key to clearly distinguishing philosophy from psychology. Picking up Lotze’s key notion of validity, he argues that Kant’s project is best understood as a study of validity: the topic of philosophy is value, or the “validity of axioms” or norms. This study of validity should be broadened to all areas of culture. This broadening of the critical project was carried further in his essay, “History and Natural Science” (1894), which argued (against the positivist theory of history), that history provides a distinct way of knowing (which he calls, “idiographic”), distinct from the natural scientific (“nomothetic”) way of knowing. Windelband was also a prolific and original historian of philosophy, culminating in 1891 with his history of philosophy from ancient to modern times (Windelband 1891). He articulated and defended a conception of doing history of philosophy (Problemgeschichte, history of philosophical problems) that became standard for the Neo-Kantians of both schools.