Immanuel Kant was the inheritor of the great pedagogical program of German scholasticism, drawing on a number of thinkers such as Wilhelm Gottfried Leibniz (especially through the works of Christian Wolff) and many, many others. At a certain point in his career, however, Kant came to the conviction that the excesses of these so-called "rationalistic" philosophers could not provide an adequate grounding for the sciences and for the moral life.

Therefore, Kant undertook a change of perspective that led to the publication of his three best known works: The Critique of Pure Reason, The Critique of Practical Reason, and The Critique of Judgment. These three texts sought to explain just what could be known within the bounds of finite human reason—thus providing a critical perspective regarding what he took to be the excesses and emptiness of the philosophy that he had taught for many years.

The notion of "Cartesian Dualism" is named after the thinker René Descartes(1596-1650)—a man who is often seen to be one of the fathers of modern philosophy. In his Discourse on Method and his Meditations on First Philosophy, Descartes makes a number of famous arguments. One of the most well known ideas is that the soul is completely distinct from the body. He concludes this from the idea that thought is clearly distinct from the notion of "body." The latter is really more of a geometrical "stuff" than anything else. He claims that even if we didn't have a body, we could still have self-consciousness.

His arguments are more complicated than this, of course, and they are open to many critiques. Be that as it may, one of the hallmarks of his philosophy is this kind of "dualism." In general a "dualism" occurs when we explain something through two different, unique principles that are not reducible to each other. Thus, for him, the human person is reduced to these two principles: soul and body. It's up to the philosopher to try to puzzle out how they are related.

In a way, all of these thinkers were influential, though in different ways. Francisco de Vitoria was a teacher in Spain whose work on natural rights is part of a broader discussion that would eventually filter through many Catholic and Protestant thinkers. These thinkers would become sources for the pivotally important Thomas Hobbes, whose best known political work is the Leviathan—a brutal but fully developed treatise on a quite domineering notion of the nation state. Likewise, Baron de Montesquieu was quite influential on many political thinkers during this period, as was Jean-Jacques Rousseau.

The most important thinker concerning the Declaration of Independence is John Locke. It is from Locke's thought that Thomas Jefferson derived his remarks regarding the rights to "life, liberty, and the pursuit of happiness." In Locke's political philosophy, he actually presents life, liberty, and property as the three fundamental rights of human persons. Locke's position was a kind of softening of the much harsher position of Hobbes, who stated that when we are not in society, we only have one fundamental right—self defense! Note, of course, that Jefferson changed "property" to "pursuit of happiness." This followed the recommendations of his fellow drafters, who hoped thereby to avoid issues that could have arisen because of a very problematic form of property in the colonies—slaves.

In his political philosophy, Jean-Jacques Rousseau discusses (among other things) the idea of the "general will" of the people. This idea can seem very horrifying—almost like a tyrannical will of the majority over the rest of the people. He means something much simpler than that. He is merely referring to the idea that in a given group of people, the people as a whole have a will that is aimed at certain common goals. Indeed, in some ways, Rousseau's thought in this regard is a kind of strange version of what some Aristotelians and Medieval Scholastics meant in their discussions of how the common good is willed by a political body. Of course, there are great differences in how they conceived of the common good and how Rousseau discussed the "general will." What remains, however, is the fact that Rousseau is, in fact, well known for using this notion in his political philosophy.

"Chekhov's Gun" is named after the Russian playwright Anton Chekhov, who once commented, "If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it absolutely must go off. If it's not going to be fired, it shouldn't be hanging there." The term is now used to describe any small element that is introduced into the story to be used later in the plotline.

W. S. Gilbert and Arthur Sullivan were a librettist and composer, respectively, who began teaming up in the 1870s to write comic operas. Throughout the next few decades, Gilbert and Sullivan wrote some of the most well known works of theater, including The Pirates of Penzance, H.M.S. Pinafore, and The Mikado. Gilbert and Sullivan's work highly influenced the development of musical theater in the twentieth century.

Henrik Ibsen wrote both of the plays Ghosts and A Doll's House. He was a 19th century Norwegian playwright. He is sometimes called the "father of realism."

The Faust story is an old one, told in traditional German folk tales, puppet plays, and songs, but Goethe retold the story of an intellectual who sells his soul to the devil to plough psychological depths. Goethe's story finds a man questing for a more fulfilling life, and being tempted by a demon to achieve this goal. Goethe's two-part play is the most widely performed and seen play in the German language.

Moliere helped popularize and develop theater during the seventeenth century by combining elaborate and genteel French comedy styles with the broader and more jovial Italian commedia dell'arte. Moliere's works such as The Misanthrope, Tartuffe, and The Miser all were essentially farces that mocked upper-class values, religious people, and social habits. These elements made Moliere equally controversial and influential in subsequent centuries.

The "Restoration" in "Restoration comedies" refers to the return of the monarchy to England under the Stuart King Charles II. Following the deeply Puritan Commonwealth of Oliver Cromwell, which banned all forms of theater and celebrations, theater companies and audiences found a taste for bawdy and over-the-top comedies that featured outlandish characters and bizarre situations.