The main theme of The Leviathan by Thomas Hobbes is an analysis of ethics and politics grounded in an assumption of radical materialism. Rather than taking as a starting point the nature of God or the good, Hobbes grounds his philosophy in purely mechanistic accounts of knowledge and human nature. Within this system, humans are by nature purely individualistic, equal in power and innate capacity, and engaged in a constant struggle for survival. Life under the natural order is "nasty, brutish and short" and lived in a state of incessant conflict. It is only by having strong central authority imposing order that civilization can be maintained. Thus Leviathan becomes a justification of monarchy on the basis of materialism.