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.

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.

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.

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?

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.

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.

Intended to be a defense of the Christian religion, Pensées is a penetrating collection of thoughts on faith, reason, and theology. Unfinished at the time of Pascal's death, the book consists of philosophical fragments on the "wretchedness" of man and the controversial schisms of the church at the time. It includes the philosopher's infamous wager encouraging belief over agnosticism, as well as his thoughts on numerous other topics. Endlessly quotable, Pensées overflows with pearls of wisdom, each elusive sentence pregnant with a universe of thought.

Perhaps the most influential science book ever written, On the Origin of Species has continued to fascinate for more than a century after its initial publication. Its controversial theory that populations evolve and adapt through a process known as natural selection led to heated scientific, philosophical, and religious debate, revolutionizing every discipline in its wake. With its clear, concise, and surprisingly enjoyable prose, On the Origin of Species is both captivating and edifying.

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".

Dedicated as few men have been to the life of reason, Bertrand Russell has always been concerned with the basic questions to which religion also addresses itself - questions about man’s place in the universe and the nature of the good life, questions that involve life after death, morality, freedom, education, and sexual ethics. He brings to his treatment of these questions the same courage, scrupulous logic, and lofty wisdom for which his other work as philosopher, writer, and teacher has been famous.

The Summa Theologica, by Thomas Aquinas, is a fundamental text in Catholic doctrine, a compendium of theology that has been studied and debated since its first publication in the 13th century. Furthermore, it has been widely regarded as one of the classics of Western philosophy, not least because, perhaps for the first time in such a systematic manner, it set out to consider the views of non-Christian figures such as Aristotle, Boethius, Muslim writers including Averroes (Ibn Rushd) and Avicenna (Ibn Sina) and the Sephardic Jewish scholar Maimonides.

Brought up in the household of a powerful Baron, Candide is an open-minded young man whose tutor, Pangloss, has instilled in him the belief that 'all is for the best'. But when his love for the baron's rosy-cheeked daughter is discovered, Candide is cast out to make his own way in the world. And so he and his various companions begin a breathless tour of Europe, South America and Asia, as an outrageous series of disasters befall them - earthquakes, syphilis, a brush with the Inquisition, murder - sorely testing the young hero's optimism.

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?

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.

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

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.

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?

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.

"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.

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.

He was the father of the occult, the founder of astrology, the discoverer of alchemy. He was Hermes Trismegistus, and as the scribe of the gods of ancient Egypt, he possessed all divine knowledge... which he passed on to humanity, though only those who have been tutored in its wonders can fully understand it.In this extraordinary 1912 book, three secret initiates to his teachings - who remain anonymous to this day - share their insight with all who seek to understand the mysterious underpinnings of the universe and our relationship with it.

Two contrasting reflections by Aristotle which cover very particular ground. In 'On the Soul', Aristotle presents his view of the 'life essence' which, he argues, is possessed by living things whether plants, animals or humans. Not a 'soul' in the generally accepted Western use of the term, this 'soul', he says, is a life force that is indivisible from the organism that possesses it.

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.

The Summa Theologica, by Thomas Aquinas, is a fundamental text in Catholic doctrine, a compendium of theology that has been studied and debated since its first publication in the 13th century. Furthermore, it has been widely regarded as one of the classics of Western philosophy, not least because, perhaps for the first time in such a systematic manner, it set out to consider the views of non-Christian figures such as Aristotle, Boethius, Muslim writers including Averroes (Ibn Rushd) and Avicenna (Ibn Sina) and the Sephardic Jewish scholar Maimonides.

The Varieties of Religious Experience is considered to be the classic work in the field. To quote Wikipedia, "James was most interested in understanding personal religious experience. The importance of James to the psychology of religion - and to psychology more generally - is difficult to overstate. He discussed many essential issues that remain of vital concern today. What makes James writing so special is that he could take a very complex subject and, without watering it down, make it understandable to 'the rest of us.'"

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.

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.

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.

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?

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.