Final answer:
Edward B. Tylor believed that over time, as societies progressed from 'savagery' to 'civilization,' their religious systems would evolve from animism to polytheism and finally to monotheism, reflecting a unilineal evolution of religious thought.
Step-by-step explanation:
The British anthropologist Edward B. Tylor proposed a hypothetical scheme which suggested that cultures progress through distinct stages from "savagery" to "barbarism" to "civilization." Considering religion, Tylor focused on the evolutionary development of religious thought from simple to complex forms. He argued, as with many anthropologists of his time who followed the unilineal evolution theory, that all societies would eventually progress along the same developmental path. Over time, he believed that as societies advanced, their religious systems would also become more sophisticated. Tylor theorized that early animistic beliefs would evolve into polytheism and eventually monotheism. However, his theory faced critique for oversimplifying and misrepresenting the complexities and unique developments of diverse cultural practices.