Political philosophy
Political philosophy is the branch of philosophy that deals with fundamental questions about politics: the existence of the state, the extent of liberty, the pursuit of justice, the source of rights and the duties of citizens. One of the earliest political philosopher was Plato of Greece, whose Republic greatly influenced later political thought. Plato's student, Aristotle, further systematized the study of politics in philosophy and his principles were carried through the Middle Ages by the Scholastic philosophers such as Thomas Aquinas. In the Renaissance era, Machiavelli started the realist approach of political theory, which was also reflected in the writings of Thomas Hobbes. Another major turning point in politcal philosophy was the Enlightenment, where the foundation of modern liberal democracy was laid.
For many political philosophers, these questions are answered in part by what has been dubbed a social contract theory accounting for the origin of governments - this approach started with Thomas Hobbes and John Locke, but has been revived in recent years with the work of the American philosophers John Rawls and Robert Nozick.
Classical political philosophy
Plato and Aristotle
Hellenism
Medieval political thought
Renaissance
The Enlightenment
Political philosophy during the period called "the Enlightenment" was marked by the repudiation of "divine rights" theory previously used to justify monarchical aboslutism, the abandonment of Aristotelian principles of Scholastic philosophy, and emphasis on reason. This trend in political theory was accompanied by simultaneous scientific progress.
Social contract theory
A breakthrough in political philosophy during this era was the emergence of social contract theory of legitimacy of the state. One of the first proponent of the theory was British philosopher Thomas Hobbes, who thought that the generation of government was from a "contract", or agreement between every man and every man to set up a government to maintain order and avoid chaos. John Locke changed the concept of social contract substantially and proposed inalienable natural rights of "life, liberty, and property". Jean-Jacques Rousseau and Immanuel Kant separately developed their own ideas on social contract and arrived at distinct conclusions on the political organization of mankind.
The Enlightenment concept of social contract was revived in the contemporary era by a philosopher of the Anglo-American analytic traiditon named John Rawls, who was influenced by Kant and expounded his theory of "original position" and its relation to political justice. Another analytic philosopher Robert Nozick produced his own ideas based on original position but drastically departed from Rawls' approach and, in fact, was a vehement critic of Rawls' conclusions.
Political turmoil and revival of conservatism
The political atmosphere during the Enlightenment saw its violent shakedown in the French Revolution and its Reign of Terror. This had led to a backlash against the previous philosophy of Enlightenment that sought to establish state with liberty and equality based on reason, and conservative theorists such as Edmund Burke of Britain and Joseph de Maistre of France gained prominence.