"The distinction between animal and man which counts is not that of the physical or the mental, which is one of relative degree, but that of the organic and the social, which is one of kind." (1917)German-American anthropologist. Along with Lowie and Mead, Kroeber was one of Boas' most successful students. Like most of the Boasians, Kroeber accepted evolution as an explanation for biological phenomena, but argued that it did not operate in humans and had no role in explaining human behavior. Instead, he staked out the position that that culture was the sole, "superorganic" determinant of human behavior. Furthermore, Kroeber held that culture was completely unique to humans and set them apart from nature. He was involved in the nature-nurture debate among American social scientists from an early stage, before World War I, and opposed eugenics and neo-Lamarckism. President of the American Folklore Society from 1906.