The field of anthropology is the study of humans through time. There are now four main subfields- Physical (biological) anthropology, cultural anthropology, archaeology, and linguistics. Anthropology was originally created in attempt to understand human differences. Samuel Morton (1799-1851), originally a physician and viewed as the first physical anthropologist, collected human skulls. He measured them and attempted to compare the sizes of five different human racial groups, trying to prove that whites had the biggest brain sizes and therefore were the most intelligent. Herbert Spencer (1820-1903) believed that traits such as a strong work ethic and morality were traits that could be passed down genetically, from parent to child. Spencer coined the phrase "survival of the fittest" and used those ideas to justify poor work conditions and racism. All of these ideas led to the rise of scientific racism where scholars used science to back up their racist ideologies, although the science they used was later proved to be wrong. Francis Galton (1822-1911), was an English anthropologist who was interested in the hereditary of intelligence and coined the term eugenics, which was the idea of only mating people with desirable traits to increase the occurrence of those traits. It was thought that since nonwhites were less intelligent, and that you could breed for higher intelligence, whites should not mate with nonwhites. Laws were passed that made interracial marriages illegal.