human nature is something we can understand and a basis on which we can found a political order
Thus, Aristotle saw human nature as essentially social, designed for the basic relationships of marriage, parenthood, and workplace; his political theory saw society as unfolding organically from the basic facts of human nature. Hobbes, on the other hand, saw humans as essentially selfish and violent; his view requires a government which strictly controls society to preserve peace and safety (Hobbes will later revise this view, which appears in the first half of his book, the Leviathan).
Before we develop any political theory, then, we must first answer this question: what are the unchanging and essential features shared by all human beings? What is it that makes us human? Across different races, religions, languages, cultures, and locations, we all have certain basic characteristics. This is why it is possible for people to understand each other, and this is the basis for any understanding of society on the one side, government on the other, and the relationship between the two. What is human nature?