Innatism is the philosophical position that corresponds to a belief in the power of nature as opposed to nurture.
According to innatist thinkers, people are born with ideas already in their minds. They argue that the mind is not really a blank slate in the way that "tabula rasa" thinkers such as John Locke argue that it is. If people have ideas and concepts in their minds innately, then nature has a great deal of influence on the human being. However, if Locke is correct and the mind is a blank slate at birth, then what we become is completely dependent on our nurture and nature has no role in defining us as human beings.