Buffon and Johann Blumenbach were believers in monogenism, the concept that all races have a single origin. They also believed in the "degeneration theory" of racial origins. They both said that Adam and Eve were Caucasian and that other races came about by degeneration from environmental factors, such as the sun and poor diet. They believed that the degeneration could be reversed if proper environmental control was taken, and that all contemporary forms of man could revert to the original Caucasian race.