John Locke and his works - particularly An Essay Concerning Human Understanding - are regularly and rightly presented as foundations for the Age of Enlightenment. His primary epistemological message - that the mind at birth is a blank sheet waiting to be filled by the experiences of the senses - complemented his primary political message: that human beings are free and equal and have the right to envision, create and direct the governments that rule them and the societies within which they live.

Immanuel Kant’s Critique of Pure Reason can lay claim to being the most important single work of modern philosophy, a work whose methodology, if not necessarily always its conclusions, has had a profound influence on almost all subsequent philosophical discourse. In this work Kant addresses, in a groundbreaking elucidation of the nature of reason, the age-old question of philosophy: “How do we know what we know?” and the limits of what it is that we can know with certainty.

Benedict de Spinoza's Ethics, first published in 1677, constitutes a major systematic critique of the traditional and religious foundations of philosophical thought. In it, Spinoza follows a logical step-by-step format consisting of definitions, axioms, propositions, proofs, and corollaries to create a comprehensive inquiry into the truth about God, nature, and humans' place within the universe. From these broad metaphysical themes, Spinoza derives what he considered to be the highest principles of religion and society and lays out an ethical system in which reason is the supreme value.

A landmark in the history of thought, Rene Descartes' Meditations helped bring critical thinking and skepticism to the Western world. Modern philosophers are still captivated by Descartes' radical and controversial departure from his previous beliefs, which has both inspired reverence and provoked anger.

Rene Descartes is often described as the first modern philosopher, but much of the content of his Meditations on First Philosophy can be found in the medieval period that had already existed for more than a thousand years. Does God exist? If so, what is his nature? Is the human soul immortal? How does it differ from the body? What role do sense experience and pure reason play in knowing?

This Leibniz collection contains some of the philosopher’s most important works and ideas, spans three decades and illuminates the fascinating intellectual journey undertaken by him in his quest for truth. A prodigious polymath, Leibniz was a mathematician, philosopher, physicist and statesman and engaged with a sweeping range of ideas and disciplines, striving throughout his life to be at the cutting edge of scientific thinking. These Principal Essays are arranged in chronological order.

The Discourse on the Method of Reason was the first true work of skepticism, a foundation of doubt which allowed a critical re-examination of all that was previously held to be true. Descartes literally revolutionized both philosophy and mathematics, and this discourse provides the means by which he approached the tangle of contemporary thought and laid the foundation of rational understanding.

René Descartes was a central figure in the scientific revolution of the 17th century. In his Discourse on Method he outlined the contrast between mathematics and experimental sciences, and the extent to which each one can achieve certainty. Drawing on his own work in geometry, optics, astronomy and physiology, Descartes developed the hypothetical method that characterizes modern science, and this soon came to replace the traditional techniques derived from Aristotle.

Philosophical Investigations was published in 1953, two years after the death of its author. In the preface written in Cambridge in 1945 where he was professor of philosophy he states: ‘Four years ago I had occasion to re-read my first book (the Tractatus Logico-Philosophicus) and to explain its ideas to someone. It suddenly seemed to me that I should publish those old thoughts and the new ones together: that the latter could be seen in the right light only by contrast with and against the background of my old way of thinking.’

Richard Dawkins, the world’s most famous evolutionary biologist, presents a gorgeously lucid, science book examining some of the nature’s most fundamental questions both from a mythical and scientific perspective. Science is our most precise and powerful tool for making sense of the world. Before we developed the scientific method, we created rich mythologies to explain the unknown. The pressing questions that primitive men and women asked are the same ones we ask as children. Who was the first person? What is the sun? Why is there night and day?

Published in 1748, An Enquiry Concerning Human Understanding is Scottish empiricist philosopher David Hume's distillation of his mature philosophy. Addressing themes including the limits of human understanding, the compatibility of free will with determinism, weaknesses in the foundations of religion, and the appeal of skepticism, An Enquiry Concerning Human Understanding is Hume's attempt to revise and clarify the ideas of his earlier A Treatise of Human Nature.

Man is born free, and everywhere he is in chains. In The Social Contract, Rousseau explores the concept of freedom and the political structures that may enable people to acquire it. He argues that the sovereign power of a state lies not in any one ruler but in the will of the general population. Rousseau argues that the ideal state would be a direct democracy where executive decision making is carried out by citizens who meet in assembly, as they would in the ancient city-state of Athens.

Aristotle was a Greek philosopher and polymath during the Classical period in Ancient Greece. His writings cover many subjects including physics, biology, zoology, metaphysics, logic, ethics, aesthetics, poetry, theatre, music, rhetoric, psychology, linguistics, economics, politics and government.

Aristotle's Metaphysics was the first major study of the subject of metaphysics - in other words, an inquiry into 'first philosophy', or 'wisdom'. It differs from Physics which is concerned with the natural world: things which are subject to the laws of nature, things that move and change, are measurable. In Metaphysics, the study falls on 'being qua being' - being insofar as it is being; the causes and principles of being, the causes and principles of substances.

The Problems of Philosophy discusses Bertrand Russell's views on philosophy and the problems that arise in the field. Russell's views focus on knowledge rather than the metaphysical realm of philosophy. The Problems with Philosophy revolves around the central question that Russell asks in his opening line of Chapter 1 - Is there any knowledge in the world which is so certain that no reasonable man could doubt it?

René Descartes was a central figure in the scientific revolution of the 17th century. In his Discourse on Method he outlined the contrast between mathematics and experimental sciences, and the extent to which each one can achieve certainty. Drawing on his own work in geometry, optics, astronomy and physiology, Descartes developed the hypothetical method that characterizes modern science, and this soon came to replace the traditional techniques derived from Aristotle.

Plagued with doubt and uncertainty in sensory knowledge, Descartes is struck with the idea that everything he knows is false. He considers the possibility that he has been deceived by an 'evil demon' and is left with nothing to lean on, until he arrives at the phrase 'cogito ergo sum' ('I think, therefore I am'). Among the most quoted philosophical works in history, Meditations on First Philosophy and Discourse on the Method together display the full workings of Descartes' skeptical method and the formation of his famous phrase.

A landmark in the history of thought, Rene Descartes' Meditations helped bring critical thinking and skepticism to the Western world. Modern philosophers are still captivated by Descartes' radical and controversial departure from his previous beliefs, which has both inspired reverence and provoked anger.

Rene Descartes, mathematician, scientist, and first "modern philosopher", wrote Meditations on First Philosophy, a six-part treatise first published in Latin in 1641, to deconstruct "belief" and, using reason and science, discuss the only things we can truly know for sure. Each of the six parts of this book represents six of Descartes’ meditations that occurred on six subsequent days, making it also, in no small part, an autobiographical piece of work.

In this monumental work of moral and political philosophy, Plato sought to answer some of the world's most formidable questions: What does it mean to be good? What enables us to distinguish between right and wrong? How should human virtues be translated into a just society? Perhaps the greatest single treatise written on political philosophy, The Republic has strongly influenced Western thought concerning questions of justice, rule, obedience, and the good life.