This paper situates Alfred Russel Wallace's spiritualist writings from his book Miracles and Modern Spiritualism (1875) against the backdrop of Victorian anthropology. It examines how he constructed his argument, and the ways in which he verified the trustworthiness of his evidence using theories and methods drawn from anthropology. Spirit investigations relied on personal testimony. Thus the key question was: who could be trusted as a credible witness? While much has been written on Wallace's inquiries into spirit phenomena, very little scholarship has taken seriously his remark about how his studies of spirits and mediums were a “new branch of anthropology.” Wallace's aim of aligning his spirit investigations to the practices of British anthropology fed into larger disciplinary discussions about the construction of reliable anthropological data. Most notably, like many of his Victorian anthropological counterparts, Wallace grounded his research in a double commitment to firsthand observation and Baconian inductivism.