René 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? Descartes stands out from his predecessors because of the method he developed to treat these and other fundamental questions.

One of the most significant books ever written by a head of state, the Meditations are a collection of philosophical thoughts by the Emperor Marcus Aurelius (121 - 180 ce). Covering issues such as duty, forgiveness, brotherhood, strength in adversity and the best way to approach life and death, the Meditations have inspired thinkers, poets and politicians since their first publication more than 500 years ago. Today, the book stands as one of the great guides and companions - a cornerstone of Western thought.

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.

By calling everything into doubt, Descartes laid the foundations of modern philosophy. With the celebrated words "I think therefore I am," his compelling argument swept aside ancient and medieval traditions. He deduced that human beings consist of minds and bodies; that these are totally distinct "substances"; that God exists and that He ensures we can trust the evidence of our senses.

The leviathan is the vast unity of the State. But how are unity, peace, and security to be attained? Hobbes’ answer is sovereignty, but the resurgence of interest today in Leviathan is due less to its answers than its methods: Hobbes sees politics as a science capable of the same axiomatic approach as geometry.

In Euthyphro, Socrates is on his way to the court, where he must defend himself against serious charges brought by religious and political authorities. On the way he meets Euthyphro, an expert on religious matters who has come to prosecute his own father. Socrates questions Euthyphro's claim that religion serves as the basis for ethics. Euthyphro is not able to provide satisfactory answers to Socrates' questions, but their dialogue leaves us with the challenge of making a reasonable connection between ethics and religion.

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.

The Republic poses questions that endure: What is justice? What form of community fosters the best possible life for human beings? What is the nature and destiny of the soul? What form of education provides the best leaders for a good republic? What are the various forms of poetry and the other arts, and which ones should be fostered and which ones should be discouraged? How does knowing differ from believing?

First published in 1859, John Stuart Mill's On Liberty is an exhaustive exploration of social and civic liberty, its limits, and its consequences. Mill's work is a classic of political liberalism that contains a rational justification of the freedom of the individual in opposition to the claims of the state.

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.

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.

Continuing where Thus Spoke Zarathustra left off, Nietzsche's controversial work Beyond Good and Evil is one of the most influential philosophical texts of the 19th century and one of the most controversial works of ideology ever written. Attacking the notion of morality as nothing more than institutionalised weakness, Nietzsche criticises past philosophers for their unquestioning acceptance of moral precepts. Nietzsche tried to formulate what he called "the philosophy of the future".

Perhaps one of the most revolutionary works of philosophy ever presented, The Phenomenology of Spirit is Hegel's 1807 work that is in numerous ways extraordinary. A myriad of topics are discussed, and explained in such a harmoniously complex way that the method has been termed Hegelian dialectic. Ultimately, the work as a whole is a remarkable study of the mind's growth from its direct awareness to scientific philosophy, proving to be a difficult yet highly influential and enduring work.

From the perspective of an unbeliever, Fear and Trembling explores the paradox of faith, the nature of Christianity, and the complexity of human emotion. Kierkegaard examines the biblical story of Abraham, who was instructed to sacrifice his son Isaac, and forces us to consider Abraham's state of mind. What drove Abraham, and what made him carry out such an absurd and extreme request from God? Kierkegaard argues that Abraham's agreement to sacrifice Isaac, and his suspension of reason, elevated him to the highest level of faith.

Aristotle's Nicomachean Ethics, said to be dedicated to Aristotle's son, Nicomachus, is widely regarded as one of the most important works in the history of Western philosophy. Addressing the question of how men should best live, Aristotle's treatise is not a mere philosophical meditation on the subject, but a practical examination that aims to provide a guide for living out its recommendations.

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.

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?

Considered by many to be Hannah Arendt's greatest work, published as she neared the end of her life, The Life of the Mind investigates thought itself, as it exists in contemplative life. In a shift from her previous writings, most of which focus on the world outside the mind, this work was planned as three volumes that would explore the activities of the mind considered by Arendt to be fundamental. What emerged is a rich, challenging analysis of human mental activity, considered in terms of thinking, willing, and judging.

"The central miracle asserted by Christians is the Incarnation. They say that God became Man. Every other miracle prepares the way for this, or results from this." This is the key statement of Miracles, in which C. S. Lewis shows that a Christian must not only accept but rejoice in miracles as a testimony of the unique personal involvement of God in his creation.

Despite the recent ferocious public debate about belief, the concept most central to the discussion "God" frequently remains vaguely and obscurely described. Are those engaged in these arguments even talking about the same thing? In a wide-ranging response to this confusion, esteemed scholar David Bentley Hart pursues a clarification of how the word "God” functions in the world’s great theistic faiths.

This simplistic and ingenious allegory from one of the fathers of Western philosophy casts light on society’s naiveté and ignorance.

Already a classic, this landmark study of early Western thought now appears in a new edition with expanded coverage of the Middle Ages. Author Anthony Gottlieb looks afresh at the writings of the great thinkers, questions much of conventional wisdom, and explains his findings with unbridled brilliance and clarity. From the pre-Socratic philosophers through the celebrated days of Socrates, Plato, and Aristotle, up to Renaissance visionaries like Erasmus and Bacon, philosophy emerges here as a phenomenon unconfined by any one discipline.

Written in 1917, The Law and the Word is a hard-to-find work by Judge Thomas Troward, a pioneer in mental science. Troward's writings and lectures greatly influenced Ernest Holmes, the founder of Religious Science and writer of The Science of Mind.

This book was one of the first to combine thought energy, scientific reasoning and testing, and creative power, and to see the interconnection of the three.

There is a cause, or a reason, behind everything that happens. This is the fundamental view behind the classical proposition the Principle of Sufficient Reason, which, in 1813, Schopenhauer chose as his subject for further examination in his doctoral dissertation On the Fourfold Root of the Principle of Sufficient Reason....

Socrates is in prison, sentenced to die when the sun sets. In this final conversation, he asks what will become of him once he drinks the poison prescribed for his execution. Socrates and his friends examine several arguments designed to prove that the soul is immortal. This quest leads him to the broader topic of the nature of mind and its connection not only to human existence but also to the cosmos itself. What could be a better way to pass the time between now and the sunset?

One of the most influential philosophers and theologians in the history of Western thought, St Thomas Aquinas established the foundations for much of modern philosophy of religion, and is famous for his arguments for the existence of God. In this cogent and multifaceted introduction to the great saint's work, Edward Feser argues that you cannot fully understand Aquinas' philosophy without his theology, and vice-versa. He covers Aquinas' thoughts on the soul, natural law, metaphysics, and more.

Twenty-seven years ago, Matthieu Ricard gave up a promising career as a scientist to study Tibetan Buddhism - not as a detached observer but by immersing himself in its practice under the guidance of its greatest living masters. Years later, this project was born, and Richard met with his father, Jean-Francois Revel - a French philosopher who became world famous for his challenges to both Communism and Christianity. At an inn, these two profoundly thoughtful men explored questions that have occupied humankind throughout its history.

Modern Man in Search of a Soul is the classic introduction to the thought of Carl Jung. Along with Freud and Adler, Jung was one of the chief founders of modern psychiatry. In this book, Jung examines some of the most contested and crucial areas in the field of analytical psychology: dream analysis, the primitive unconscious, and the relationship between psychology and religion.

Growing up in London, Katherine Jegede was always searching for a philosophy to make sense of life. When she found the mind-as-creator philosophy of Neville Goddard, she thought she had found it. Falling victim to a terrible crime, however, caused Jegede to rethink everything she thought she knew. Rather than abandoning Neville's ideas, however, she discovered within them a new source of strength and fortitude. She not only rebounded from her crisis, but also used Neville's creative-mind principles to become a television presenter, something she had never before imagined possible.

Immanuel Kant's Fundamental Principles of the Metaphysics of Morals, first published in 1785, lays out Kant's essential philosophy and defines the concepts and arguments that would shape his later work. Central to Kant's doctrine is the categorical imperative, which he defines as a mandate that human actions should always conform to a universal, unchanging standard of rational morality.

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.

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.

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.

By calling everything into doubt, Descartes laid the foundations of modern philosophy. With the celebrated words "I think therefore I am," his compelling argument swept aside ancient and medieval traditions. He deduced that human beings consist of minds and bodies; that these are totally distinct "substances"; that God exists and that He ensures we can trust the evidence of our senses.

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.