ALFRED ADLER — Another of Freud's students, Adler believed that feelings of inferiority rather than sexuality were the main motivating unconscious force in people.
ANAXAGORAS — He took the theories of four roots a step further by declaring that reality can be reduced to an infinite number of “seeds.” Not unlike Empedocles's hypothesis, these seeds contain elements of everything and are in everything, yet certain elements are there in greater abundance, creating life's myriad diversity. And in lieu of Empedocles's Love and Strife theory, Anaxagoras postulated on the existence of a Nous or omniscient yet impersonal Mind that gave order and constancy to the universe.
ANAXIMANDER — A younger contemporary of Thales, he didn't believe that it was one of the four familiar elements that was the basic stuff of the world; rather, all those elements and more all comprised a common element he, for lack of a better word, called “The Boundless.” All things arise from The Boundless (ápeiron in Greek), and all things return to The Boundless. This foreshadows Einstein's dictum that “Matter can neither be created nor destroyed.”
ANAXIMENES — A pupil of Anaximander who digressed from his mentor's theory by singling out air as the root of all things. We need air as much as water. He believed the soul was composed of air.
ANSELM OF CANTERBURY — A Benedictine monk and teacher who ultimately became the Archbishop of Canterbury, the highest religious office in England. He sought to distinguish between philosophy and theology. The famous maxim of Anselm was “Credo ut intelligam,” which means “I believe that I may understand.” He is most famous for his Ontological Argument, which “proves” the existence of God.
THOMAS AQUINAS — A primary Catholic thinker who sought to Christianize Aristotle similarly to the way that Augustine adapted Neoplatonism to Christian teaching, he also reconciled the dilemma of Faith versus Reason. He is famous for his five points that prove the existence of God, and he spoke of Universals, his revised version of that Platonic Forms.
ARISTOTLE — Aristotle studied under Plato as a student at the latter's Academy for twenty years. He was a prodigy and generally regarded as Plato's heir apparent. However, he disagreed with the master on several key points. Aristotle is famous for the syllogism, which is a logical argument that takes two truths, connects them, and arrives at a third truth.
AUGUSTINE OF HIPPO — He was born and died in the last days of the Roman Empire and serves as a bridge between the classical and the medieval worlds. Augustine's candid autobiography, Confessions, chronicles his struggles with faith and earthly pleasures and contains the famous and ironic prayer, “God grant me chastity … but not yet.” Augustine used Neoplatonic philosophy to defend, endorse, and affirm Christian theology. Augustine attempted to explain some of the many mysteries of Christianity through the philosophies of Plato.
MARCUS AURELIUS — He was a foremost Stoic whose collection of journal entries, written in between vanquishing barbarian hordes, Meditations, is a quintessential distillation of Stoic thought and practice.
FRANCIS BACON — This British politician and businessman took a scientific approach to philosophy. He studied the world as an empirical observer would and attempted to avoid bringing his preconceptions and prejudices into the proceedings. Bacon proposed that, in order to truly understand the world, we must first be aware of the various obstacles and distractions that prevent us from seeing things clearly.
ROGER BACON — Bacon was a Franciscan monk who is regarded as a forerunner of the modern scientist. He sought to incorporate the academic disciplines of mathematics and language into theology and philosophy through his book Opus Major. Bacon proposed that there are three ways to gain knowledge: authority, reason, and experience. He breaks experience into the realms of the internal and external. External experience is awareness of physical reality and the world of the senses. Internal experience is similar to Augustine's “illumination,” a little help from the person upstairs.
GEORGE BERKELEY — He believed that everything was an idea, even physical matter. Only minds and the ideas they generate are real, according to this Irish clergyman. He is considered to be the founder of the modern version of Idealism, a belief that goes back to Plato in its original presentation. Unlike the closet atheism of Locke, Berkeley flatly states that God is responsible for the introduction and dissemination of perceptions into the human brain. These things we perceive do not exist outside the mind. They have no substantial reality of their own.
FRANZ BOAS — An influential anthropologist who sought to make anthropology more respectable, he believed in fieldwork, or living among the civilization you were studying for an extended period of time. He also rejected the ethnocentric and downright racist views of many of his predecessors. He trained a whole generation of anthropologists, and his work was the basis for the practice of cultural relativism.
ALBERT CAMUS — This French-Algerian man of letters wrote The Stranger, The Mythof Sisyphus, and other novels, plays, and nonfiction works. He, along with Jean-Paul Sartre, was a premier exponent of Existentialism. Camus was given the Nobel Prize for literature in 1957 and died tragically in a car accident in 1960. Although primarily known as a novelist and playwright, these fictional devices exposed existentialism to a wide audience.
CICERO — The famous Roman senator, lawyer, orator, and philosopher lived and died dur-ing some of the most turbulent times in ancient history. Cicero “Romanized” the Greek philosophers in Latin translations designed to bring the classics to the Romans. It is said he was inventive in his translations, and as a lifelong lawyer and politician, he had ulterior motives in his efforts to bring philosophy to the Roman Empire. Ever the pragmatist, he intended to use philosophy as a tool to further his political goals and advance the glory that was Rome. Though he was largely linked to the Roman branch of Skepticism, he was also a premier practitioner of Eclecticism.
AUGUSTE COMTE — This French philosopher is generally regarded as the father of modern sociology. Comte sought to employ the same methods that scientists had used in the investigation and exploration of the physical world and apply them to the study of human affairs.
CHARLES DARWIN — The most famous proponent of the theory of evolution, he proposed the theory of natural selection in his book, On the Origin of Species. This theory maintains that certain characteristics and qualities in a species enabled it to survive, and thus those characteristics were passed on to the progeny, over time altering the species in significant ways. Species went off in other directions while their progenitors remained stagnant or died away.
JACQUES DERRIDA — This contemporary French philosopher started the philosophical school called deconstruction, which is the process of breaking down something (in Derrida's case, language) to show that what is being stated is in fact inherently false. He thumbs his nose at traditional philosophy by saying that philosophy is logocentric.
RENÉ DESCARTES — This French philosopher is often called the Father of Modern Philosophy. He started out his career as a mathematician and is credited with discovering the concept of Analytic Geometry. He uttered perhaps the most famous sentence in the history of philosophy: “I think, therefore I am.” Everything could be questioned, but one thing remained a fact: the thinking of the thinker.
EMILE DURKHEIM — He bridged the disciplines of sociology and the equally new notion of anthropology. Durkheim also founded the school of thought called Functionalism, which maintains that a society, in essence, took on a personality of its own and could be objectively viewed the way a scientist or physician may regard a living organism. He proposed that cultures have a collective consciousness, where the values and beliefs held by a culture direct the behavior of its members without them even knowing it.
RALPH WALDO EMERSON — Emerson was a writer and lecturer whose famous works include Nature and Self-Reliance, which expressed the Transcendentalist philosophy. He viewed every individual as having full and free access to the Over-Soul. We are all something like cells in the giant organism that is God/Nature. We can access this collective unconsciousness and experience total interconnectedness with our fellows and the natural world. He believed that evil is not a force unto itself but merely arises from the absence of good. He considered poets to be the modern mystics and prophets and directly influenced and inspired America's greatest poet, Walt Whitman. His influence in philosophy and literature had a profound impact on the American culture.
EMPEDOCLES — Empedocles can be compared to Pythagoras in that he combined the scientific and spiritual, yet his area of expertise was medicine rather than mathematics. He also offered the theory that it was not one element at the center of it all, but rather that the roots of all found elements — fire, air, earth, and water — could be found in everything. The four roots would exist in different degrees. Obviously, water would have a preponderance of water roots, but the others would be there to a lesser degree. And in an ancient Greek variation on the yin/yang belief of coexisting complementary opposites, he added that the entities he called Love and Strife were complementary forces that impacted on the world as they knew it.
EPICURUS — One of the most misinterpreted philosophers in the pantheon of great thinkers. His name and his philosophy became synonymous with wanton hedonism. Although Epicurus put great stock in the pursuit of pleasure, his definition of pleasure would be more akin to the delights enjoyed by the couch potato as opposed to the libertine. Epicurus led a restful, contemplative life, eating modestly, drinking moderately, and philosophizing for the most part from a prone position on his hammock.
MICHEL FOUCAULT — This recent French philosopher is considered a postmodernist. Foucault's major works include Madness and Civilization, wherein he chronicled Western society's changing views toward mental illness over the centuries. Foucault's other major work is called Discipline and Punish, wherein he critiques the world's various penal systems making the case that, in the Western world at least, the employment of torture and physical abuse in modern prison systems has merely switched the destructive emphasis from body to soul.
SIGMUND FREUD — One of the most famous and influential psychologists of the twentieth century, his name is known by even those who don't know much about psychology. Two of the techniques of Freudian psychoanalysis are the interpretation of dreams and free association. Freud also came up with the infamous theory of the Oedipus Complex.
GORGIAS — He didn't put much stock in the notion of virtue, but instead felt that the power of persuasion was key. His philosophy is summed up in this three-pronged theory: Nothing exists, if anything did exist we could not know about it, and if something existed and someone knew about it, he or she couldn't communicate that awareness to others.
MARTIN HEIDEGGER — His existential philosophy influenced Camus, Sartre, and many modern philosophers that followed. Unlike Nietzsche, who posthumously suffered the slander of being labeled a Nazi, Heidegger has earned the title fair and square. The German publicly endorsed Hitler and the Nazis in the 1930s. He shifted the focus from the examination of the conscious to experiencing the state of simply “being there,” in his book, Being and Time.
HERACLITUS — Nicknamed “the Obscure,” Heraclitus was a philosopher who was known as something of a downer. His theory that everything is composed of fire, if taken metaphorically, is expressed in his belief that everything is in flux. You couldn't even step into the same river twice, according to him, because the flowing water was not the same water you dipped your big toe into mere seconds before.
THOMAS HOBBES — This English philosopher rejected Descartes's dualism and touted the theory that ours is a mechanistic and materialistic universe. An attempt to synthesize Empiricism and Rationalism, it is also quite a pessimistic viewpoint and paints man as a less than noble piece of work. His most famous work is called The Leviathan. The titular leviathan of Hobbes's tome is a society without order. Hobbes felt that without order, society would violently self-destruct.
DAVID HUME — A Scottish philosopher who was influenced by and expanded upon the ideas of John Locke and George Berkeley, Hume not only denied the existence of the material substances of Locke, but also the spiritual world of ideas proposed by Berkeley. Hume also rejected the existence of the individual self. You do not exist. According to Hume, you are nothing more than what he called “a collection of different perceptions.” He dismissed the scientific principle of cause-and-effect and stated that knowledge of anything as certainty is just plain impossible, except maybe mathematics.
EDMUND HUSSERL — The founder of phenomenology, this German philosopher endeavored to study the mind itself, not the outside world of things and events that the mind perceive. The proper study of consciousness lies in the mind, according to Husserl. He called this phenomenological reduction.
WILLIAM JAMES — The Father of American Psychology and the brother of the novelist Henry James, his two-volume Principles of Psychology was the bible for a generation of American psychologists. His approach was Functionalist, proposing that the important purpose of psychological study was to examine the functions of the conscious. This involved studying selected subjects over a lengthy period of time, which consisted of observation and tests and was called longitudinal research.
CARL GUSTAV JUNG — The most famous follower of Sigmund Freud, Jung's most famous theory is that of the collective unconscious. This is a shared memory of symbols, imagery, and memories that he called archetypes, which harken back to the dawn of human consciousness and are common in all cultures and civilizations. Jung also proposed that within every man there is an inner woman and within every woman there is an inner man.
SØREN KIERKEGAARD — He was a literary figure in Denmark who used irony to make his points. As a result, it is often hard to tell when he is being serious and when he is pulling our philosophical leg. Kierkegaard is considered to be the first existentialist. His views on alienation, the angst that plagues people, and the inherent absurdity of life influenced Jean-Paul Sartre, Albert Camus, and other twentieth-century existentialists. They, however, were atheists while Kierkegaard remained a Christian throughout his life.
GOTTFRIED LEIBNIZ — While Spinoza spoke of modes, Leibniz believed that reality was made up of what he called monads. Like Democritus and the Atomists, Leibniz theorized that the smallest particle was called a monad. It was indivisible like an atom was once believed to be, and each monad was as unique as a fingerprint. Everything, including people, is composed of monads, according to Leibniz.
LEUCIPPUS AND DEMOCRITUS — The first to theorize that the world was composed of tiny particles called atoms. These particles were invisible to the human eye yet ubiquitous and their myriad combinations, comprising what we commonly call reality. Democritus built on the theories of Leucippus by suggesting that atoms were indivisible.
JOHN LOCKE — Locke was a British Empiricist who believed that all knowledge was gained through experience. There was no such thing as innate ideas, as he called them. He is famous for the theory of the tabula rasa, which means “blank slate” in Latin. Locke proposed that the human mind is a complete void upon birth and gradually accumulates data as it is exposed to life and its many sensory experiences.
KARL MARX — He was the architect of what became modern socialism and communism, ideologies that went on to change the face of the globe and the state of the world in ways that Marx himself may never have imagined. A student of philosophy, he, along with Friedrich Engels, is the author of the world-altering tome, The Communist Manifesto. He sought social reform to combat the injustices of the Industrial Revolution.
MONTESQUIEU — Montesquieu was a noted jurist who spoke of relativism as it pertains to the law. Relativism is the belief that what is good for the goose may not necessarily be good for the gander. Montesquieu also proposed the notion of a separation of powers in a government. He advocated a series of checks and balances in order to provide balance and thwart one element of government gaining more power than another.
FRIEDRICH WILHELM NIETZSCHE — Perhaps the most controversial and most misunderstood philosopher, he was as much a literary figure as a philosopher. He had no formal philosophy and basically ranted in the form of aphorisms, short pithy quips, and pungent observations. Some of these notions include God is dead, the advocacy of the Superman, the theory of eternal recurrence, and many more hot topics. His main targets were Western Civilization and Christianity. A sensitive soul plagued by health problems, he ultimately descended into madness and never recovered.
PARMENIDES — The anti-Heraclitus; he wrote in direct response to him. Simply put, he believed that there is no flux; in fact, everything is stagnant. “It is” was his credo.
Being is immutable and constant, and change is an illusion.
JEAN PIAGET — His main claim to fame is the work he did with children. After years of working in schools and interviewing thousands of children, the Swiss psychologist identified four stages of childhood development. The sensorimotor stage, from birth to age two, involves the mastering of motor controls and learning to deal with the physical world. In the preoperational stage, from ages two to seven, the child focuses on verbal skills and communication. Children begin to deal with numbers and other complex concepts in what Piaget called the concrete operational stage, and logic and reason evolves in the formal operational stage.
PLATO — Plato was Socrates's most famous protégé. He continued the Socratic legacy while building on it with his own theories. Plato was a firm believer in Ideas or, as they are also called, Forms.
PLOTINUS OF ALEXANDRIA — The founder of Neoplatonist thought, he established a school in Rome. Neoplatonism was the last shout of ancient Greek philosophizing.
PRODICUS — A rhetorician who, according to most accounts, was unabashedly in it for the money. Plato frequently satirized him as a pedantic lecturer on the niceties of language above all else. Eloquent and popular as he was, the officials of Athens saw fit to execute him for corrupting the young.
PROTAGORAS — The first Sophist, he had a successful career and enjoyed great fame in his lifetime. “Man is the measure of all things” was his credo. This was not to suggest the nobility and evolutionary superiority of the species. It is actually an extreme case of relativism, moral and otherwise. “Anything goes” was the natural devolution of such a principle. If it feels good, do it. If it gets you ahead even at the expense of another, go for it.
PYRRHO OF ELIS — The founder of the Skeptic school of philosophy, he saw the road to happiness as doing as little as possible. Repose was the only recourse for the truly wise man. The only path to peace is to suspend judgment, because no worldview is any better than another. Do not believe anything you see or hear. Do not have any opinions. There is no such thing as good or evil. Rather than promote chaos and confusion, Pyrrho believed that to accept this is the only way to live.
AYN RAND — An American novelist and philosopher, she is famous for the novels The Fountainhead and Atlas Shrugged. Her philosophy is called Objectivism. She put reason before emotion, and individualism over groupthink, and thought egotism was a good thing and altruism was a negative character trait.
CARL ROGERS AND ABRAHAM MASLOW — The pioneers of what was called humanistic psychology, they were dissatisfied with the rigidities of psychoanalysis and behaviorism. Their theories, neither psychoanalytic nor behaviorist, came to be called the third force. These two men saw psychology as a means to help people fulfill their maximum potential. Rogers felt that all people are instilled with an innate drive to “be all that they can be,” and it was the role of psychotherapy to facilitate this process. Abraham Maslow devised a hierarchy of needs, which is the path a person takes from the basic needs of survival on the road to the achievement of their potential. The lowest levels on the scale would be food and shelter, while further up the scale would be things like security and love. The top of the list of needs is what Maslow called self-actualization.
JEAN JACQUES ROUSSEAU — This French philosopher and social critic also was one of the earliest practitioners of the tell-all memoir. His candor was shocking in his day.
BERTRAND RUSSELL — A British philosopher, Nobel laureate, and one of the most influential philosophers of the twentieth century, Russell was also a pacifist. The fact that he also lived to the ripe old age of ninety-eight meant that he protested every major conflict from World War I to the Vietnam War. He did, however, take a patriotic stand during World War II, but in the Cold War, he remained a staunch antinuclear weapons activist. At the advanced age of eighty-nine, he was arrested at an antinuclear protest.
JEAN-PAUL SARTRE — The other French existentialist of the twentieth century was also a novelist and dramatist as well as the author of philosophical works and political polemics. He is more famous for the novel Nausea, the play No Exit, and the nonfiction work Being and Nothingness. He was also awarded the Nobel Prize for literature, but unlike his fellow French existentialist Albert Camus, he turned it down.
JOHN DUNS SCOTUS — Scotus was a Franciscan monk who endorsed many of the precepts of Augustine, yet differed on other key elements, including the necessity of “illumination.” Humans have the intellect to comprehend God and his wonders without a celestial cheat sheet. Being a cleric and a man of his time, dogma rules as far as Scotus is concerned. He spins the notion of Universals by suggesting that they exist as Forms (to be found in the mind of God) and as part of the physical things they represent (as perceived in the mind of man). While Aquinas has the intellect pre-eminent over the human will, Scotus said that will is more important than intellect. This led to a great medieval debate known as the Thomist-Scotist controversy.
SENECA — The Roman playwright and noted Stoic took his own life when he fell out of favor with the notorious emperor Nero.
B. F. SKINNER — The most famous Behaviorist, he believed that people's behavior could be changed through the process of conditioning. The famous example of this involves the rat in a box (designed by Skinner and appropriately named the Skinner Box). The rat learned that if it presses a lever, a food pellet is released. This positive reinforcement ensures that the behavior will be repeated and is called operant conditioning.
SOCRATES — This dynamic and controversial Athenian figure spent a lifetime in the public square engaging in dialogues with the young men of Athens. His singular method of posing questions to his intellectual quarry and drawing responses is called
HERBERT SPENCER — This British philosopher put his spin on the evolutionary theory by applying it to humanity and calling it survival of the fittest. This form of social Darwinism was often used to justify colonialism and the xenophobic European feelings of superiority.
BARUCH SPINOZA — Spinoza believed in pantheism, meaning that God is present in all things. Like Descartes, Spinoza wrestled with the idea of Substance. Descartes called the infinite substance God, while Spinoza called it Nature. His belief that God is Nature and that nature is one substance that can shape-shift into various forms that he called modes is not unlike the Monist philosophies of the Presocratics.
THALES — Thales of Miletus is often designated as the first “official” philosopher. He is regarded as the founder of natural philosophy. He proposed that everything is composed of water. Though Thales could not have known that the human body is composed of mostly water, he was on to something, simplistic as his theories may seem today. His rational approach of not attributing anything and everything to “the gods” paved the way for the scientific method. He was revered as a sage in his lifetime and long after his death.
HENRY DAVID THOREAU — Famous for the book Walden, a journal of his solitary existence in a cabin on Walden Pond, Thoreau was an eloquent spokesperson for the Transcendentalist philosophy. Another philosophy that Thoreau espoused, and was later made better known and practiced in the twentieth century, was civil disobedience.
VOLTAIRE — One of the most famous and infamous philosophers of the Enlightenment, he was a celebrity and a controversial figure in his lifetime. His satirical pieces landed him in the Bastille, the notorious French prison, on more than one occasion, but these incarcerations did not cause his quill pen to run dry.
MAX WEBER — He was a German thinker who also took a jaundiced view of capitalism and sought to understand its emergence in the Western World rather than in another culture in another part of the world. He linked the rise of capitalism with the Protestant Work Ethic. Whereas Marx believed that economics motivated human thought, Weber believed the opposite: Human ideas brought about particular economic systems. And while Marx spoke of class struggles and ultimately class warfare, the word Weber used to describe the division of societies was stratification. Weber also addressed the rise of bureaucracies in Europe. He actually liked them! He thought they were the ideal organizing principle in the new industrial societies of Europe in the nineteenth century.
WILLIAM OF OCKHAM — Famous for the theory that has come to be known as Ockham's Razor, Ockham believed that when all is said and done in this crazy world, the simplest answer is usually the right one.
LUDWIG JOSEF JOHAN WITTGENSTEIN — This Austrian philosopher studied with Bertrand Russell and became an influential advocate of analytic and linguistic philosophy. In 1918, Wittgenstein completed the Tractatus Logico-philosophicus, which he called the “final solution” to all problems of philosophy. However, in later years, he rejected his own conclusions in the Tractatus and wrote yet another seminal work of modern philosophy called Philosophical Investigations.
MARY WOLLSTONECRAFT — This was a woman truly ahead of her time. She wrote one of the most famous novels in the history of the English language (Frankenstein) and was a feminist rallying cry almost 200 years before the modern Feminist movement came into being.
ZENO — Zeno is best known for a couple of famous paradoxes. The first one explains how, sitting in your room, you can never really reach the door. If the distance between two points is composed of an infinite number of points, then we can bisect that line. And we can keep bisecting the areas we previously bisected ad infinitum. Hence, you potentially have an infinite amount of space in a finite distance between two points and can never really get anywhere.
The second Zeno paradox deals with motion. When you move from one place to another, you reach the midway point before the final destination. And before you get to the halfway mark, you reach the halfway mark of the midway point. Ergo, you have to travel an infinite number of points in a finite amount of time. And that is impossible, right?
ZENO OF CYPRUS — Founder of the Stoic school, he used to lecture from his porch, which was called a stoa, hence the name Stoic. The word “stoic” has remained in the language and defines a person who accepts life's slings and arrows without whining about it.