An 18th-century German philosopher whose monumental influence on all subsequent Western philosophical thought is difficult to understate. Although Kant’s complex writings covered (and revolutionized) virtually every field of philosophy, de Beauvoir focuses on his ethics: essentially, Kant thought that action is moral when the principles or motives behind an action could hold universally for all rational beings. While de Beauvoir agrees with Kant that freedom is the fundamental characteristic of human life and morality should be tied to the character of the human will (rather than handed down by a Godlike legislator), she does not think that morality is about whether one’s principles are consistent in principle, but rather about the concrete circumstances, conditions, and effects of people’s actions. For instance, whereas Kant would reject all killing in any situation because it would not be consistent with human freedom as a universal principle, de Beauvoir accepts such violence in the kind of particular situations when, even though killing is a violation of freedom, it is likely to ultimately help expand human freedom (for instance, as in killing one’s oppressors).