Van Sertima states near the end of the book that all civilizations are capable of independent invention, and that he aims to place his claims on the spectrum between diffusionism and isolationism, or the idea that cultures separated geographically are capable of inventing similar things without interaction between the two. However, some of the biggest resting points of his theory attribute Mesoamerican pyramids, mummification, symbolism, mythology, calendar technology, and much of the art to African influence and guidance. Critics in anthropology and archaeology have stated that "They Came Before Columbus" portrays Native Mesoamerican peoples as inferior and incapable of developing highly sophisticated civilizations, cultures, and technologies without the influence of Africans arriving by boat as “gods” in their eyes, as Van Sertima puts it. The claims in this book are not generally accepted in the scientific fields of archaeology and anthropology.