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  Philosopher (c. 470 BCE–c. 399 BCE)
 Socrates was a Greek philosopher and the main source of Western thought. Little is known of his life except what was recorded by his students, including Plato.
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  Academic, Philosopher, Political Scientist, Journalist, Historian (1588–1679)
 Thomas Hobbes, an English philosopher in the 17th century, was best known for his book Leviathan (1651) and his political views on society.
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  Academic, Philosopher, Scientist, Mathematician (1596–1650)
 Philosopher and mathematician René Descartes is regarded as the father of modern philosophy for defining a starting point for existence, “I think; therefore I am.”
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  Philosopher (1632–1677)
 Dutch philosopher Benedict de Spinoza was expelled from his synagogue for his rationalist ideas about God, which he later published in his 1677 work, Ethics.
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  Philosopher (1724–1804)
 Immanuel Kant was a German philosopher during the Enlightenment era of the late 18th century. His best known work is the Critique of Pure Reason.