kinship between humans and other animals, as well as their emphasis on the connection between them through metempsychosis. English writer and animal rights advocate Henry S. Salt in his 1892 book Animals' Rights, argued that for humans to do justice to other animals, that they must look beyond the conception of a "great gulf" between them, claiming instead that we should recognize the "common bond of humanity that unites all living beings in one universal brotherhood". Edward Payson Evans, an American scholar and animal rights advocate, in Evolutional Ethics and Animal Psychology, published in 1897, was critical of anthropocentric psychology and ethics, which he argued "treat man as a being essentially different and inseparably set apart from all other sentient creatures, to which he is bound by no ties of mental affinity or moral obligation". Evans argued that Darwin's theory of evolution implied moral obligations towards enslaved humans and nonhuman animals, asserting that these obligations not only implied that cruelty to slaves must be mitigated and that slavery be abolished, but also that nonhuman animals need more than just kind treatment; they require rights to protect them and that would be enforced if violated. Evans also contended that widespread recognition of the kinship between humans and even the most insignificant sentient beings would necessarily mean that it would be impossible to neglect or mistreat them. An 1898 article published in The Zoophilist, entitled "Anthropocentric Ethics", argued that the earliest civilizations, before Christianity, considered tenderness and mercy towards sentient organism to be a law. It asserted that Zarathustra and the Buddha espoused this philosophy and that early Greek philosophers, similarly to Brahmins and Buddhists followed the doctrine of metempsychosis, which led eventually to the adoption of vegetarianism. The article also contended that this unquestioned truth of psychical homogeneity between humans and animals was carried into the early Christian era, with the Greek philosopher Celsus making its denial a serious criticism of Christianity. The article argued that early Christian writers, such as Origen, considered animals to be mere automata, created for the benefit of humans and that this belief persists to the present day. It concluded that "Animal Psychology and its relation to Evolutionary Ethics is a subject which is attracting the attention of scientists and moralists alike, and can no longer be treated with indifference, much less with contempt. We must enlarge our conceptions of the intention than that the whole