Throughout the nineteenth century, evidence and debates about the role of faith in the unity and/or original diversity of humankind shaped metropolitan theories as well as observations from the periphery. Most observers were aware of the debates on the issue and structured their reports according to their positions which could encompass a range of theological, political, and scientific theories. The question of 'The Faculty of Faith' was loaded with implications for the conceptualization of relationships between human groups and eventually between human beings and animals. Along with other Evangelical missionaries such as Threlkeld and Inglis, Brown constantly and anxiously patrolled contemporary debates about human difference and was alert to the political, religious, and moral implications of philosophical and scientific theories. Brown's anthropological interests and the terms on which he agreed to debate human difference were directed by his Christian insistence on human similitude. While he joined many of his fellow missionaries in accepting the logic of social evolutionist theory, he simultaneously sought to temper the implications of its findings. Theorists such as Tylor and Müller consistently argued for the psychic unity of man and the universal intellectual and religious capabilities of all human beings. Müller, secure in his own faith, was never concerned with suggestions that human beings were progressing beyond religion. Tylor, however, mapped out a particularly modernist position where faith became the preserve of the primitive and the less advanced and could only be successfully investigated by the post-Christian scientific anthropologist. Lubbock and Darwin sought to downplay the sophistication of native faith in order to minimize the division between people and animals and advance the theory that human ability, whether religious, moral, or intellectual, was neither innate nor universal but developed through time and could be mapped on to contemporary human populations.

By the end of the nineteenth century, the issue of the 'faculty of faith' appeared to have lost its relevance to the discipline of anthropology. Anthropologists generally seemed to have accepted the Tylorian position that all belief in spirits was evidence of religion. However, the evolutionist theory on the gradual development of religious belief from animism to monotheism to science was a popular idea that maintained the opposition between 'civilized' and 'primitive'. While it is beyond the scope of this chapter to move into the twentieth century, it would seem that secular modernism created new implications for the question of primitive belief. In the popular imagination, the question suggested two possible answers: either indigenous peoples had maintained 'traditional' beliefs which were clearly outdated by rational thought; or they had been 'coerced' into Christianity, a level of religious belief which many believed to be beyond their cultural and moral capacity.