that the weak and feeble should perish. This association with Nazism, coupled with increasing recognition that it was scientifically unfounded, contributed to the broader rejection of social Darwinism after the end of World War II. Criticism and controversy Multiple incompatible definitions Social Darwinism has many definitions, and some of them are incompatible with each other. As such, social Darwinism has been criticized for being an inconsistent philosophy, which does not lead to any clear political conclusions. For example, The Concise Oxford Dictionary of Politics states: Part of the difficulty in establishing sensible and consistent usage is that commitment to the biology of natural selection and to "survival of the fittest" entailed nothing uniform either for sociological method or for political doctrine. A "social Darwinist" could just as well be a defender of laissez-faire as a defender of state socialism, just as much an imperialist as a domestic eugenist. Nazism, eugenics, fascism, imperialism Social Darwinism was predominantly found in laissez-faire societies where the prevailing view was that of an individualist order to society. A different form of social Darwinism was part of the ideological foundations of Nazism and other fascist movements. This form did not envision survival of the fittest within an individualist order of society, but rather advocated a type of racial and national struggle where the state directed human breeding through eugenics. Names such as "Darwinian collectivism" or "Reform Darwinism" have been suggested to describe these views to differentiate them from the individualist type of social Darwinism. As mentioned above, social Darwinism has often been linked to nationalism and imperialism. During the age of New Imperialism, the concepts of evolution justified the exploitation of "lesser breeds without the law" by "superior races". To elitists, strong nations were composed of white people who were successful at expanding their empires, and as such, these strong nations would survive in the struggle for dominance. With this attitude, Europeans, except for Christian missionaries, seldom adopted the customs and languages of local people under their empires. Peter Kropotkin and mutual aid Peter Kropotkin argued in his 1902 book Mutual Aid: A Factor of Evolution that Darwin did not define the fittest as the strongest, or most clever, but recognized that the fittest could be those who cooperated with each other. In many animal societies, "struggle is replaced by co-operation". It may be that at the outset Darwin himself was not fully aware of the