Philosophy Logic

Each year,John Brockman, publisher of Edge.org, challenges some of the world's greatest scientists, artists, and philosophers to answer a provocative question crucial to our time. In 2014 he asked 175 brilliant minds to ponder: What scientific idea needs to be put aside in order to make room for new ideas to advance? The answers are as surprising as they are illuminating.

Logic is often perceived as having little to do with the rest of philosophy, and even less to do with real life. In this lively and accessible introduction, Graham Priest shows how wrong this conception is. He explores the philosophical roots of the subject, explaining how modern formal logic deals with issues ranging from the existence of God and the reality of time to paradoxes of probability and decision theory. Along the way, the basics of formal logic are explained in simple, non-technical terms, showing that logic is a powerful and exciting part of modern philosophy.

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.

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."

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.

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.

Confucius knew all about life and told us how to behave, but we can't find out precisely what he was up to. His well-meaning platitudes, quaint maxims, and quasi-enigmatic anecdotes combined to produce an ideal philosophy for civil servants. It would appear that his aim was to turn his pupils into good government officials, but his teachings succeeded beyond his wildest expectations, providing rules of conduct and spiritual fodder for more than two thousand years.

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.

Rene Descartes spent most of his childhood in solitude, a situation that also came to characterize his adult life. Fortunately, these countless lonely hours helped Descartes produce the declaration that changed all philosophy: "I think, therefore I am." Eventually convincing himself to doubt and disregard sensory knowledge, Descartes found he could prove his existence through his thoughts. This internal information, he believed, was the true reality and external forces were hopelessly deceiving.

In an age when philosophers had scarcely glimpsed the horizons of the mind, a boy named Aristocles decided to forgo his ambitions as a wrestler. Adopting the nickname Plato, he embarked instead on a life in philosophy. In 387 B.C. he founded the Academy, the world's first university, and taught his students that all we see is not reality but merely a reproduction of the true source. And in his famous Republic he described the politics of "the highest form of state."

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.

Upon its first English publication in 1959, Popper's The Logic of Scientific Discovery revolutionized thinking about the scientific method. Largely an exploration of the demarcation problem, or what distinguishes science from non-science, Popper introduced and defended his concept of falsifability -- that scientific systems are ones open to empirical disconfirmation -- against the prevailing views of his day.

"If we accept Wittgenstein's word for it," Paul Strathern writes, "he is the last philosopher. In his view, philosophy in the traditional sense was finished."

With Hegel, philosophy became very difficult indeed. His dialectical method produced the most grandiose metaphysical system known to man. Even Hegel conceded that "only one man understands me, and even he does not." Hegel's system included absolutely everything, but its most vital element was the dialectic of the thesis, antithesis, and synthesis. This method sprang from Hegel's ambition to overcome the deficiencies of logic and ascended toward mind as the ultimate reality.

In Rousseau we encounter a walking ego, naked sensibility. Feeling triumphs over intellectual argument in his works, which are both deeply stirring and deeply inconsistent. Yet while his contemporaries Kant and Hume may have been superior academic philosophers, the sheer power of Rousseau's ideas was unequaled in his time. It was he who encouraged the introduction of both liberty and irrationality into the public domain.

For more than a century, from 1900 to 2006, campaigns of nonviolent resistance were more than twice as effective as their violent counterparts in achieving their stated goals. Authors Erica Chenoweth and Maria J. Stephan detail the factors enabling such campaigns to succeed and, sometimes, causing them to fail.

In a world where fake news stories change election outcomes, has rationality become futile? In The Art of Logic in an Illogical World, Eugenia Cheng throws a lifeline to listeners drowning in the illogic of contemporary life.

In St. Augustine in 90 Minutes, Paul Strathern offers a concise, expert account of St. Augustine's life and ideas and explains their influence on man's struggle to understand his existence in the world. The book also includes selections from St. Augustine's work, a brief list of suggested readings for those who wish to delve deeper, and chronologies that place St. Augustine within his own age and in the broader scheme of philosophy.

One of our greatest philosophers and scientists of the mind asks where the self comes from - and how our selves can exist in the minds of others. I Am a Strange Loop argues that the key to understanding selves and consciousness is the "strange loop" - a special kind of abstract feedback loop inhabiting our brains. The most central and complex symbol in your brain is the one called "I". The "I" is the nexus in our brain, one of many symbols seeming to have free will and to have gained the paradoxical ability to push particles around, rather than the reverse.

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.