11 Philosophers Who Made the World Stop and Think

470 BCE-399 BCE

Socrates is a name you probably have heard time and time again. That’s because he helped lay the foundation for Western thought and moral philosophy with the development of his Socratic method. The Grecian thinker’s approach to logical argumentation involved asking a series of questions to encourage dialogue about complex ideas. At the time, it was lauded by some but infuriated others because it could make them appear foolish.

Socrates used this method to challenge widely accepted beliefs about the role of gods in society, the nature of democracy, and the relationship between appointed leaders and the people. He was put on trial for his theories in 399 BCE, convicted by a jury, and sentenced to death, but it was too late to contain his revolutionary ideas.

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384 BCE-322 BCE

You’re likely also familiar with Aristotle, the ancient Greek philosopher and scientist described as one of the greatest thinkers in politics, psychology, and ethics. Dubbed the “father of Western logic,” Aristotle developed a universal system of deductive reasoning that aimed to help humans understand everything they possibly could about reality.

He believed the validity of an argument is determined by its structure rather than its content and that deduction and inference could be used to collect information to support an argument. His estimated 200 works influenced over seven centuries of philosophy and laid the groundwork for modern-day logic.

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1596-1650

A French philosopher, Descartes’ ideas went against the prevailing Aristotelian and Scholastic philosophies of the 1600s that depended mostly on sensory perception as our main source of truth. He believed in clearing all preconceived and inherited notions and starting anew.

With this approach, Descartes came to the conclusion that, if we are able to doubt our own existence, then we must exist, leading to his famous quote: ”I think, therefore I am.” He published these words—a fundamental principle of his philosophy—in Discourse on the Method (1637), which had a major influence on modern philosophy and recognized the importance of mathematics and scientific thinking in the field.

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1632-1704

Locke was known for his works on political philosophy, epistemology, and education, with perhaps his most influential being 1689’s Two Treatises of Government. This was the publication that brought forth the idea of a “social contract” in which the consent of the governed is essential for legitimate rule.

Born in England, Locke worked with Lord Ashley early on in his medical studies; Ashley became Earl of Shaftesbury and greatly influenced Locke’s political outlook. In his works, Locke denounced the concept of tyranny and argued that everyone has the right to life, liberty, and property. His philosophies influenced the leaders of the American and French revolutions, who made direct connections between Locke’s principles and their own.

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1723-1790

A Scottish philosopher and economist, Smith introduced the concept of a political economy with his publication of The Wealth of Nations in 1776. A country’s wealth, he argued, isn’t measured by the quantity of gold and silver in its possession, but rather, by the total of its production and commerce—a metric we know today as gross domestic product (GDP).

Smith also argued in favor of free-market economies and an economic system driven by people’s self-interest, led by an “invisible hand” that allows the economy to regulate itself. The Wealth of Nations is often considered a foundational work of classical economics.

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1759-1797

In her 38 years of life (she died 10 days after giving birth to Frankenstein author Mary Shelley), Wollstonecraft cemented her lasting impact as a British philosopher and writer. She is best known for publishing A Vindication of the Rights of Woman in 1792, arguing that the educational system was designed to turn women into helpless ornaments of the household.

Her call for women to have access to the same opportunities as men was revolutionary in her time but also stirred tremendous controversy. By the 19^th and 20^th centuries, however, Wollstonecraft’s feminist philosophy came to inspire crusaders of the women’s rights movements in both the United States and Britain.

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Keep Reading: The Women Behind the 19^th Amendment

1818-1883

The anticapitalist works of German philosopher and socialist Karl Marx form the basis of Marxism, a political and economic ideology driven by a set of theories that predict the rise of a classless society where workers share ownership of the means of production. As the founder of a Communist Correspondence Committee, Marx published the political pamphlet commonly known as The Communist Manifesto in 1848.

Marx also went on to author the first volume of Das Kapital in 1867 after shifting his focus more to capitalism and economic theory. Initially, his ideas had little impact, but by 1950, nearly half of the global population lived under Marxist governments.

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1868-1963

Among many things, Du Bois was a philosopher, economic historian, sociologist, and leader in the African American rights movement of the first half of the 20^th century. His 1903 collection of 14 essays, The Souls of Black Folk, is among his most influential works in the history of sociology. In it, Du Bois describes the “double consciousness” of African Americans, in which their identities as people of both African and American descent creates a distinct experience from either individual background. Philosophers and scholars have continued to expand on Du Bois’ concept of double consciousness in the decades since.

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Related: How W.E.B. Du Bois Helped Create the NAACP

1905-1980

French philosopher Sartre caused us to think more deeply about why we exist and the meaning of life. He wrote his most influential work, Being and Nothingness (1943), while spending nine months as a prisoner of war after being drafted into the French army, and he drew upon his wartime experiences to write the book. As part of his existentialist philosophy, Sartre proposed that humans can and should make their own meaningful decisions in life, without help from external forces, and that we have no predetermined purpose. His works greatly influenced 20^th century sociology, postcolonial theories, and other disciplines as we know them today.

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1905-1982

Although Rand’s philosophy of objectivism was poorly received during her lifetime, it ultimately became widely influential in how we think about the concept of reality. The Russian-born American author of both fiction and nonfiction encouraged the pursuit of rational self-interest in a world where reality and the nature of events occur independent of human thought, feelings, and beliefs.

Rand often integrated her philosophy into her novels, including the widely known The Fountainhead (1943) and Atlas Shrugged (1957). Her philosophy continues to influence advocates of individual reason and economic freedom, and her books are still in print today.

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1908-1986

The modern feminist movement can trace its roots, in part, to the works of French philosopher De Beauvoir, whose nearly 1,000-page The Second Sex, published in 1949, challenges the patriarchal status quo and the lower status granted to women. While now known as one of the most influential early feminist works, at the time its publication led to great controversy; some critics went so far as to label the book as pornography. Before she died in 1986, De Beauvoir challenged gender norms, called for equality, and helped women view their place in society differently.

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