Georg Wilhelm Friedrich Hegel
Hegel was a German philosopher who promoted a systematic approach to philosophy. This consisted of dividing philosophy into distinct categories concerned with logic, nature, and spirit. He was an idealist who believed that history progressed in accordance with the development of a "world spirit," the weltgeist. His ideas of human nature were based on the idea that humans have an innate desire to be recognized and that historical progress is based around competition between social "masters" and "slaves" to be recognized. Hegel's work is strongly associated with his promotion of the ideals of the Prussian state he lived in. Prussia was the name of some of the European territories that later became known as Germany. His philosophical work was concerned more generally with the promotion of reason and individual liberty. He had a major influence on later thinkers, especially Karl Marx, who borrowed much from Hegel's view of historical evolution and especially Hegel's dialectical method. Hegel's dialectic held that ideas progressed in the following way: an idea (thesis) met its opposite (antithesis) and in the conflict between the two produced a new idea (synthesis).
Karl Marx was a political radical whose work was devoted to analyzing capitalism and promoting its overthrow. His work fused philosophy, economics, history, and sociology. Marx proposed a view of history in which society is defined by its economic system, which changed over time in an evolutionary process. His idea of historical evolution was borrowed from Hegel, as was his use of the dialectical method. The engine of history in Marx's view is class struggle: the antagonism between the haves and have-nots in a given society, defined by their relationship to the economic "means of production." Marx viewed capitalism as a predatory and unjust system. His written works, chiefly in The Communist Manifesto and Capital, were devoted to providing an analysis of capitalism that could be used to plot its overthrow. After capitalism, Marx believed, would come a just society in which the means of production would be owned by and used for the good of all, which he called communism.
John Locke was an English philosopher. He studied at Oxford University before qualifying as a medical doctor. His friendship with the Earl of Shaftesbury introduced Locke to the reformist politics that would go on to influence his later work. It is for these political beliefs that Locke spent periods of his life in exile from England. Locke's great contribution to Enlightenment thinking came in the form of his Two Treatises of Government (1689). This text attacked the idea that royal authority was based on divine right and instead promoted an ideal of rational government based on the consent of the governed. He borrowed from Thomas Hobbes the idea that humanity without government existed in a primitive and deadly "state of nature." Locke was thus an early promoter of liberal ideals of personal liberty, the "social contract," and respect for private property rights.
Thomas Hobbes was an English philosopher and political theorist. His chief concern was with how societies could be structured to ensure that people can live together harmoniously. In his masterwork Leviathan he explored this idea in depth. He believed that humanity before civilization lived in a "state of nature" that was characterized by the "war of all against all." This was the ultimate justification, Hobbes thought, for the institution of a powerful state with a divinely-appointed sovereign at its head. Although this government was tyrannical, it was the only sure defense against the ruin and misery of the state of nature. Hobbes's work was developed by later thinkers like John Locke, and he is thus thought of as one of the early architects of liberal political theory.