The Enlightenment was in compliment to the Scientific Revolution. Where the Scientific Revolution catered to the "hard sciences" of math, chemistry, and physics, the Enlightenment brought about a major influx of people to the "soft sciences" of philosophy and social science. The major figures of the Enlightenment focused most of their work around the lives and social constructs of people.

Mary Wollstonecraft was one of the founding voices of the feminist movement. She argued that women were not naturally inferior to men and pushed to have men and women recognized as equals. A Vindication of the Rights of Women was published in 1792. Letters on the French Revolution was published in 1790 by Edmund Burke. "Ode on the Peace" was a poem published by Helen Maria Williams in 1801. The Theory of Moral Sentiments was published in 1759 by Adam Smith.

Niccolo Machiavelli's 1513 treatise The Prince described how a ruler should maintain political power. Prior to Machiavelli, political theory typically described how rulers ought to rule based on specific moral and Christian principles. In The Prince, Machiavelli instead advocates for a more realistic mode of governance not restricted by such lofty concerns.

Quotation adapted from The Prince by Niccolo Machiavelli (1513; trans. Mariott 1908)

Absolutism, as exemplified by rulers such as Louis XIV of France, was a movement toward political centralization in Europe. As trade from overseas imperial holdings and expensive, gunpowder dependent-armies grew in importance, they increasingly transferred an edge to the crown in the old feudal struggles. Absolute rulers curbed the rights and privileges granted to smaller feudal nobles, and as a result contributed to the general breakdown of local variation and the rise of nationalism within Europe.

John Locke pushed the epistemological notion of the Tabula Rasa, meaning blank slate. He said that when humans are born they have no knowledge and are therefore ready to be taught everything about the world. Therefore, the environment we grow up in will give us a perspective of world events.

Mein Kampf was Hitler’s manifesto that was published in two volumes and was started while Hitler was in jail for leading an uprising against the government in Munich. The first part came out in 1925 and the second part in 1926. It detailed Hitler’s views on who and what he blamed for the poor state of Germany. His primary blame fell on the Jews and what he felt was their desire to control the world. The book became very popular in Germany and contributed to Hitler’s reputation and rise to power. Das Kapital (1867) was written by Karl Marx and edited by Friedrich Engels.

Slavs were one of the dominant ethnic groups in Eastern and Southern Europe and were ruled by the Austro-Hungarian empire throughout much of the nineteenth century. The rising influence of nationalism in this time period led to the Slavic people campaigning for self-government. Ultimately, however, two competing schools of thought emerged: Austro-Slavism, which sought to have the Slavic people protected by the might of the Austro-Hungarian Empire, and Pan-Slavism, which sought an independent Slavic state under the protection of the Russian Empire.

Voltaire believed in the separation of Church and State. This was in large part due to the carnage that he had seen when religion became a part of the national government. Wars fought between nations of different religions, and people forced to worship in the church of the national leader led to countless conflicts.

Mary Wollstonecraft was a founding voice of Feminism in the late 1700's. Her treatise A Vindication of the Rights of Woman is her most famous work, and is an outline of the idea that women are not inferior to men, and deserve the same rights.

Social Darwinism was an interpretation of the theory of natural selection that emerged in the second half of the nineteenth century. Social Darwinism essentially maintains that in human populations, just like in animal populations, natural selection is at work and only the fittest, smartest, and strongest will survive. It provided a convenient excuse for the abuses committed during the New Imperialism era, as it allowed European intellectuals to claim "natural superiority" over other races and defend their otherwise morally reprehensible actions. Of course, Social Darwinism was not universally propounded in this time period, but in the years since, it has come to be widely associated with Herbert Spencer. Spencer was one of the most famous philosophers of his time and an ardent believer in the benefits of competition.