Grete Hermann was a Kantian philosopher in the once prestigious but today largely forgotten scientifically oriented tradition of Jakob F. Fries, Ernst F. Apelt and Leonard Nelson , all philosophers who had a background in mathematics and physics as well as good friendships with the contemporary luminaries in those fields. Although originally a mathematician, Hermann became Nelson's assistant, working closely with him on his ethical and political work. The ultimate philosophical foundation of that work was called, in the wake of Kant's critical philosophy , a "deduction of the moral law" . In part because of the crisis of the principle of causality brought about by the advent of quantum physics, Hermann was dissatisfied with Nelson's use of that principle in his "deduction of the moral law". Her objections, independent of but largely parallel to those of her contemporaries, the philosophers Ludwig Wittgenstein and Wilfrid Sellars, make an original use of some concepts drawn from her study of quantum theory and her discussions with Werner Heisenberg and Carl Friedrich von Weizsäcker .