Soon after the "Origin" was published in 1859, critics derided his description of a struggle for existence as a Malthusian justification for the English industrial capitalism of the time. The term "Darwinism" was used for the evolutionary ideas of others, including Spencer's "survival of the fittest" as free-market progress, and Ernst Haeckel's polygenistic ideas of human development. Writers used natural selection to argue for various, often contradictory, ideologies such as laissez-faire dog-eat-dog capitalism, colonialism and imperialism. However, Darwin's holistic view of nature included "dependence of one being on another"; thus pacifists, socialists, liberal social reformers and anarchists such as Peter Kropotkin stressed the value of co-operation over struggle within a species. Darwin himself insisted that social policy should not simply be guided by concepts of struggle and selection in nature.