The Great Chain of Being
The Great Chain of Being is an 18th century concept of the hierarchy of beings, from God down to the lowest forms of life such as plants and insects. Due to this concept, many resulting viewpoints existed in the 18th century. One of these is the idea that all other created beings below man were created for his use. Reason being the only dividing line between man and beast. Groups of people such as the Hottentots were considered to be on the lowest rung of mankind, close to animals, and not attributed with intellect. This idea allowed 18th century British to seem justified in seeing the Hottentots, as well as other cultures they deemed "uncivilized", as physiologically different to the point that it was used as a justification for slavery.
picture is from :http://depts.washington.edu/chid/chid110/lectures99/week2/aristotle.GIF