One of the two major philosophical traditions of the twentieth century was linguistic analysis, derived largely from Wittgenstein. The other, diametrically opposed, came from Heidegger, and its fundamental question was, "What is the meaning of existence?" For Heidegger, this question could not simply be "analyzed away". It was beyond the reach of logic or reason. It was the primary "given" of every individual life. To confront it, Heidegger needed to develop an entire new form of philosophy.

With Friedrich Nietzsche, philosophy was dangerous not only for philosophers but for everyone. His ideas presaged a collective madness that had horrific consequences in Europe in the early 1900s. Though his philosophy is more one of aphorisms than a system, it is brilliant, persuasive, and incisive. His major concept is the will to power, which he saw as the basic impulse for all our acts. Christianity he saw as a subtle perversion of this concept, thus Nietzsche's famous pronouncement, "God is dead."

Immanuel Kant taught and wrote prolifically about physical geography yet never traveled further than forty miles from his home in Kvnigsberg. How appropriate it is then that in his philosophy he should deny that all knowledge was derived from experience. He insisted that all experience must conform to knowledge. According to Kant, space and time are subjective; along with various "categories," they help us to see the phenomena of the world, though never its true reality.

Aristotle wrote on everything from the shape of seashells to sterility, from speculations on the nature of the soul to meteorology, poetry, art, and even the interpretation of dreams. Apart from mathematics, he transformed every field of knowledge that he touched. Above all, Aristotle is credited with the founding of logic. When he first divided human knowledge into separate categories, he enabled our understanding of the world to develop in a systematic fashion.

Just a century after it had begun, philosophy entered its greatest age with the appearance of Socrates, who spent so much of his time talking about philosophy on the streets of Athens that he never got around to writing anything down. His method of aggressive questioning, called dialectic, was the forerunner of logic; he used it to cut through the twaddle of his adversaries and arrive at the truth. Rather than questioning the world, he believed, we would be better off questioning ourselves.

David Hume reduced philosophy to ruins: he denied the existence of everything, except our actual perceptions themselves. I alone exist, he argued, and the world is nothing more than part of my consciousness. Yet we know that the world remains, and we go on as before. What Hume expressed was the status of our knowledge about the world, a world in which neither religion nor science is certain.

During his lifetime, Jean-Paul Sartre enjoyed unprecedented popularity for a philosopher, due partly to his role as a spokesman for existentialism at the opportune moment, when this set of ideas filled the spiritual gap left amidst the ruins of World War II. Existentialism was a philosophy of action and showed the ultimate freedom of the individual. In Sartre's hands, it became a revolt against European bourgeois values.

Schopenhauer, the "philosopher of pessimism", makes it very plain that he regards the world and our life in it as a bad joke. But if the world is indifferent to our fate, it doesn't thwart us on purpose. The world's facade is supported by what Schopenhauer calls the Universal Will, blind and without purpose. This Will brings on all our misery and suffering; our only hope is to liberate ourselves from its power and from the trappings of individualism and egoism that are at its mercy.

Karl Marx's devastating critique of capitalism, and his proposal of communism as the answer to the failings of the capitalist system, bore their greatest fruits in the twentieth century with the formation of the communist state in the Soviet Union. This great venture has now all but completely failed. Yet the force of the communist belief offered the prospect of "justice on this earth" to countless numbers. And Marx's critique has influenced generations of thinkers who call themselves Marxists.

Kierkegaard wasn't really a philosopher in the academic sense. Yet he produced what many people expect of philosophy. His subject was the individual and his or her existence, the "existing being." In Kierkegaard's view, this purely subjective entity lay beyond the reach of reason, logic, philosophical systems, theology, or even "the pretenses of psychology." Nonetheless, it was the source of all these subjects. The branch of philosophy to which Kierkegaard gave birth has come to be known as existentialism.

At the beginning of his career, Joseph Campbell developed a lasting fascination with the cultures of the Far East, and explorations of Buddhist and Hindu philosophy later became recurring motifs in his vast body of work. However, Campbell had to wait until middle age to visit the lands that inspired him so deeply. In 1954, he took a sabbatical from his teaching position and embarked on a year-long voyage through India, Thailand, Cambodia, Burma, Hong Kong, Taiwan, and finally Japan.

The Blind Watchmaker, knowledgably narrated by author Richard Dawkins, is as prescient and timely a book as ever. The watchmaker belongs to the 18th-century theologian William Paley, who argued that just as a watch is too complicated and functional to have sprung into existence by accident, so too must all living things, with their far greater complexity, be purposefully designed. Charles Darwin's brilliant discovery challenged the creationist arguments; but only Richard Dawkins could have written this elegant riposte.

This audiobook is about luck, or more precisely, how we perceive and deal with luck in life and business. It is already a landmark work, and its title has entered our vocabulary. In its second edition, Fooled by Randomness is now a cornerstone for anyone interested in random outcomes.

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.

Ellenberg chases mathematical threads through a vast range of time and space, from the everyday to the cosmic, encountering, among other things, baseball, Reaganomics, daring lottery schemes, Voltaire, the replicability crisis in psychology, Italian Renaissance painting, artificial languages, the development of non-Euclidean geometry, the coming obesity apocalypse, Antonin Scalia's views on crime and punishment, the psychology of slime molds, what Facebook can and can't figure out about you, and the existence of God.

Kierkegaard wasn't really a philosopher in the academic sense. Yet he produced what many people expect of philosophy. His subject was the individual and his or her existence, the "existing being." In Kierkegaard's view, this purely subjective entity lay beyond the reach of reason, logic, philosophical systems, theology, or even "the pretenses of psychology." Nonetheless, it was the source of all these subjects. The branch of philosophy to which Kierkegaard gave birth has come to be known as existentialism.

David Hume reduced philosophy to ruins: he denied the existence of everything, except our actual perceptions themselves. I alone exist, he argued, and the world is nothing more than part of my consciousness. Yet we know that the world remains, and we go on as before. What Hume expressed was the status of our knowledge about the world, a world in which neither religion nor science is certain.

Immanuel Kant taught and wrote prolifically about physical geography yet never traveled further than forty miles from his home in Kvnigsberg. How appropriate it is then that in his philosophy he should deny that all knowledge was derived from experience. He insisted that all experience must conform to knowledge. According to Kant, space and time are subjective; along with various "categories," they help us to see the phenomena of the world, though never its true reality.

Schopenhauer, the "philosopher of pessimism", makes it very plain that he regards the world and our life in it as a bad joke. But if the world is indifferent to our fate, it doesn't thwart us on purpose. The world's facade is supported by what Schopenhauer calls the Universal Will, blind and without purpose. This Will brings on all our misery and suffering; our only hope is to liberate ourselves from its power and from the trappings of individualism and egoism that are at its mercy.

With Friedrich Nietzsche, philosophy was dangerous not only for philosophers but for everyone. His ideas presaged a collective madness that had horrific consequences in Europe in the early 1900s. Though his philosophy is more one of aphorisms than a system, it is brilliant, persuasive, and incisive. His major concept is the will to power, which he saw as the basic impulse for all our acts. Christianity he saw as a subtle perversion of this concept, thus Nietzsche's famous pronouncement, "God is dead."