12 Famous Philosophers and Their Guiding Principles

Raphael, "School of Athens" (detail of Plato and Aristotle), 1509-1511. Stanza della Segnatura, Palazzi Pontifici, Vatican.

The term “philosophy” derives from the Greek word philosophia which translates to a “love of wisdom,” coined by pre-Socratic thinkers such as Pythagoras in the 6th century B.C. These ancient Greek philosophers were influential in laying the foundations for the modern world; searching for meaning in everyday life and shaping their musings into a system of thoughts documented in books and manuscripts, letters, plays, and other media.

What is Philosophy?

Philosophy can be described as the rational, abstract, and methodical consideration of reality. Philosophy has been a central fixture in the history of civilization, from ancient Greece to modern day. In the centuries that have passed, notable philosophers both young and old have produced original thoughts and made contributions to all industries and disciplines including politics, mathematics, literature, art, and science. Below are some of the most influential philosophers, their schools of thought, and what we can learn from their forward-thinking approach.

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Confucius (551–479 B.C.)

La Morale de Confucius. Sold for €100 via Arenberg Auctions (December 2018).

Confucius, also referred to as Kong Qui or K’ung Fu-tzu, was a Chinese philosopher, teacher, and political figure largely considered the father of the Eastern style of thought. His teachings focused on creating ethical social relationships, setting educational standards, and promoting justice and honesty.

Guiding Principle

His social philosophy was based on the principle of ren—loving others—and he believed this could be achieved using the Golden Rule: “What you do not wish for yourself, do not do to others.”

Socrates (c. 469–399 B.C.)

Socrates was a Greek philosopher and is considered the primary source of Western thought. Because he could neither read nor write, much of what we know of his life was recorded by his students Plato and Xenophon. His “Socratic method” laid the groundwork for Western systems of logic and philosophy, delivering a belief that through the act of questioning, the mind can manage to find truth.

Guiding Principle

Socrates believed that philosophy should achieve practical results for the greater well-being of society. He emphasized the idea that the more a person knows, the greater his or her ability to reason and make choices that will bring true happiness.

Plato (c. 428–348 B.C.)

The Republic of Plato. Sold for $4,500 via Sotheby’s (June 2005).

Greek philosopher Plato was a student of Socrates and later became a teacher of Aristotle. He was a priori, a rational philosopher who sought knowledge logically rather than from the senses. He went on to establish the Academy in Athens, one of the first institutions of higher learning in the Western world.

Guiding Principle

Plato’s logic explored justice, beauty, and equality, and contained discussions in aesthetics, politics, language, and cosmology—the science of the origin and development of the universe.

Aristotle (384–322 B.C.)

The Works of Aristotle. Sold for €160 via Bubb Kuyper (May 2016).

Considered one of the greatest thinkers in politics, psychology, and ethics, Aristotle learned from Plato after enrolling in his Academy at age seventeen. Later, he went on to tutor Alexander the Great. Aristotle focused on a posteriori routes of knowledge, a term popularized by Immanuel Kant where conclusions are formed based on actual observation and data.

Guiding Principle

Aristotle’s intellectual knowledge spanned every known field of science and arts, prompting him to idealize the Aristotelian syllogistic, a belief that logical argument applies deductive reasoning to arrive at a conclusion based on two or more propositions assumed to be true.

Dante (1265–1321)

Dante was a Medieval Italian poet and moral philosopher regarded as the father of the modern Italian language. He is best remembered for his poetic trilogy, The Divine Comedy, which comprised of sections that represented three tiers of the Christian afterlife: purgatory, heaven, and hell. The poem features an array of learning, an analysis of contemporary problems, and creativity in language and imagery.

Guiding Principle

Dante’s important theoretical works included discussions of rhetoric surrounding moral philosophy and political thought.

Pascal (1623–1662)

Blaise Pascal was a French mathematician, physicist, and religious philosopher who laid the fountain for the modern theory of probabilities, a branch of mathematics concerned with the analysis of random phenomena.

Guiding Principle

In 1657, Pascal published Les Provinciales under the pseudonym Louis de Montalte, a series of eighteen letters that defended Jansenist over Jesuit theologies. He also propagated a religious doctrine that taught the experience of God through the heart rather than through reason, contrary to the beliefs of French philosopher René Descartes.

John Locke (1632–1704)

Two Treatises of Government. Sold for $2,125 via Swann Auction Galleries (April 2015).

John Locke was an English philosopher and Enlightenment thinker who came to be known as the Father of Classical Liberalism. Throughout his studies, he made valuable contributions to modern theories of a limited, liberal government. His most notable work, Essay Concerning a Human Understanding, offers an analysis of the human mind and its acquisition of knowledge.

Guiding Principle

Locke’s thinking emphasized the notion that we should acquire ideas through our experience of the world. His logic later influenced philosophers like Voltaire and Rousseau.

Voltaire (1694–1778)

Francois Arouet, better known for his pen name “Voltaire,” is largely considered one of the greatest French Enlightenment writers. He produced thousands of letters, books, pamphlets, essays, plays, among other forms of writing, most of which were centered on religion and politics. One of his most famous works was Candide, a satirical novella that pokes fun at the philosophical optimism proclaiming that all disaster and human suffering is part of a benevolent cosmic plan.

Guiding Principle

Though Voltaire’s outright skepticism of the government and church caused great controversy during his time, he remained a progressive thinker regarding issues of civil rights and advocated for the importance of freedom of religion, speech, and the right to a fair trial.

Immanuel Kant (1724–1804)

Critik der reinen Vernunft. Sold for $780 via Swann Auction Galleries (March 2017).

Immanuel Kant was a German philosopher whose thinking revolved around metaphysics, a philosophical study that examines the fundamental nature of reality. His best-known work, Critique of Pure Reason, determines the limits and scope of metaphysics, combining reason with experience that moves beyond that of traditional philosophy.

Guiding Principle

Kant was one of the foremost thinkers of the Enlightenment, and a large part of his work addresses the question, “What can we know?” Kant argued that we can only have knowledge of things that are possible to experience. Further, he believes that we can know the natural, observable world, but we cannot have answers to many of the deepest questions of metaphysics.

Mary Wollstonecraft (1759–1797)

Mary Wollstonecraft was an English writer and intellect who advocated for women’s equality within society. As an ardent feminist, she believed both men and women should be treated as equal beings with a social mandate. Her best-known publication, A Vindication of the Rights of Woman, is considered the first great feminist treatise. In it, she argued that women deserve the same fundamental rights as men and should have an education commensurate with their position in society.

Guiding Principle

Wollstonecraft was an fierce advocate for women’s rights, arguing that women deserve the same fundamental rights as men and should have an education commensurate with their position in society.

Ayn Rand (1905–1982)

Atlas Shrugged. Sold for $1,300 via Swann Auction Galleries (May 2018).

Russian-American author and philosopher Ayn Rand rejected collectivist values in favor of individual self-interest, an ideal evident in her first novel We the Living. She promoted the philosophy of Objectivism, which she describes as “the concept of man as a heroic being, with his own happiness as the moral purpose of his life, with productive achievement as his noblest activity, and reason as his only absolute.” This belief was realized in her successful novel Atlas Shrugged, as well as in courses, lectures, and other literary works.

Guiding principle

While Rand was a passionate advocate of the philosophy of objectivism, her political philosophy placed emphasis on individualism, the constitutional protection of individual rights to life, liberty, and property, and limited government.

Simone de Beauvoir (1908–1986)

Simone de Beauvoir is a French writer, existentialist philosopher, and social theorist who paved the way for the modern feminist movement. She published countless works, both fiction and nonfiction, often having existentialist themes. Her most notable book, The Second Sex, discusses the treatment of women throughout history and the oppression they endured.

Guiding principle

While her novels focused on existential themes, de Beauvoir’s philosophies were heavily influenced by the historical materialism of Karl Marx and the idealism of Immanuel Kant.

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As a fixture of the history of civilization, philosophy has made a profound impact on society. Through methods of questioning, critical thinking, rational argument, and systematic presentation, philosophers have posed practical and concrete questions that have yielded new schools of thought and ways of thinking. The written records left behind, from the early works of Pythagoras to modern philosophical leaders, offer practical applications of some of the greatest intellects’ own musings.

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Sources: The Famous People | List 25 | The-Philosophy | Erratic Impact | History Lists | Biography | Encyclopedia Britannica