In contrast to Rousseau, Aristotle argued that human beings are not naturally equal. The two share the view, however, that a constitution establishes the common interest of the whole. Indeed, for Aristotle, the individual does not flourish outside the community, whose primary function is to promote and secure flourishing. Like his teacher, Plato, Aristotle's political theory is deeply connected to his ethical theory. For Aristotle, in fact, ethics is preparatory to politics.
Hugo Grotius's work profoundly influenced philosophy, law, political theory, and relevant areas of study. His contributions to natural law theory generally promote the view that certain societal norms have their basis in nature. Thus, acceptable and unacceptable behaviors are so by nature.
Thomas Hobbes's political philosophy is derived from his view that reality is exclusively material, which is to say, only material things exist. According to Hobbes, outside of a social contract, human life is miserable. It is only by entering into a compact that individuals have a chance of living well—or at least, more safely than they are alone. Hobbes's view vests authority and responsibility in an individual sovereign.
Niccolò Machiavelli is often called the father of modern political philosophy. His seminal work, The Prince, offers advice to would-be rulers. This advice focuses on what a would-be prince should do to retain power.
Charles-Louis de Secondat, baron de La Brède and de Montesquieu
Montesquieu articulated a theory of the separation of governmental powers. This view was influential on framers of subsequent constitutions.
Along with Aristotle, Plato is one of the greatest philosophers. Having written on virtually every subject, Plato's philosophy is systematic. This means, in part, that his political theory is intimately connected with his theories of reality (metaphysics) and knowledge (epistemology). According to Plato, only a republic ruled by philosopher kings and queens will be just.