On September 26, 1889, German philosopher Martin Heidegger was born. He is best known for his existential and phenomenological explorations of the "question of Being". His best known book, Being and Time, is considered one of the most important philosophical works of the 20th century.
On August 17, 1586, German theologian, author, and mathematician Johann Valentin Andreae was born. He claimed to be the author of the Chymische Hochzeit Christiani Rosencreutz anno 1459 (1616, Strasbourg, the Chymical Wedding of Christian Rosenkreutz), one of the three founding works of Rosicrucianism, a philosophical secret society said to have been founded in late medieval Germany by Christian Rosenkreutz. Rosicrucianism holds a doctrine or theology "built on esoteric truths of the ancient past", which, "concealed from the average man, provide insight into nature, the physical universe and the spiritual realm."
On August 11, 1464, German philosopher, theologian, jurist, and astronomer Nikolaus of Cusa (in latin: Nicolaus Cusanus) passed away. He is considered as one of the first German proponents of Renaissance humanism. His best known work is entiteled 'De Docta Ignorantia' (Of the Learned Ignorance), where also most of his mathematical ideas were developed, as e.g. the trial of squaring the circle or calculating the circumference of a circle from its radius.
On July 13, 1527, Welsh mathematician, astronomer, astrologer, occultist, navigator, imperialist and consultant to Queen Elizabeth I, John Dee was born. He is considered one of the most learned men of his age. Besides being an ardent promoter of mathematics and a respected astronomer, in his later years he immersed himself in the worlds of magic, astrology and Hermetic philosophy. One of his aims was attempting to commune with angels in order to learn the universal language of creation.
On July 11, 1382, significant philosopher of the later Middle Ages Nicole Oresme passed away. As for many historic people of the middle ages, his actual birthdate is unknown and can only be fixed to a period between 1325 and 1330. Nicole Oresme besides William of Ockham or Jean Buridan -- a French priest who sowed the seeds of the Copernican revolution in Europe -- is considered as one of the most influential thinkers of the 14th century and he wrote influential works on economics, mathematics, physics, astrology and astronomy, philosophy, and theology.
On July 2, 1877, German poet, novelist, painter, and Nobel Laureate Hermann Hesse was born. He is best known for his novels 'Steppenwolf', 'Siddhartha', or 'The Glass Bead Game', in which he explores the individual's search for authenticity, self-knowledge and spirituality.
On July 1, 1742, German scientist, satirist and Anglophile Georg Christoph Lichtenberg was born. He is remembered best for his posthumously published notebooks, which he himself called Sudelbücher, a description modeled on the English bookkeeping term "scrapbooks", and his aphorisms.
On June 16, 1723 (June 5 according to the old Julian calendar), Scottish moral philosopher and a pioneer of political economy Adam Smith was born. He is one of the key figures of the Scottish Enlightenment and is best known for two classic works: The Theory of Moral Sentiments (1759), and An Inquiry into the Nature and Causes of the Wealth of Nations (1776)
On June 12, 1659 (other sources report June 11, 1659 - according to the Julian calendar July 13), Japanese Samurai Yamamoto Tsunetomo was born. He is best known for the publication of his compiled commentaries and aphorisms about the life of the Samurai under the title of Hagakure, a word that can be translated as either In the shadow the Leaves or The Hidden Leaves.
On May 29, 1880, German historian and philosopher Oswald Arnold Gottfried Spengler was born. He is best known for his book The Decline of the West (Der Untergang des Abendlandes), published in 1918 and 1922, covering all of world history. He proposed a new theory, according to which the lifespan of civilizations is limited and ultimately they decay.
On May 5, 1818, German philosopher and revolutionary socialist Karl Marx was born in Trier, Germany. Hes is best known for his publications 'The Communist Manifesto' and 'The Capital', as well as his ideas have played a significant role in the establishment of the social sciences and the development of the socialist movement.
On April 8, 1859, German philosopher and mathematician Edmund Gustav Albrecht Husserl was born. He is best know as the founder of the 20th century philosophical school of phenomenology, where he broke with the positivist orientation of the science and philosophy of his day, yet he elaborated critiques of historicism and of psychologism in logic.
On March 31, 1596, French philosopher, mathematician, and writer René Descartes was born. The Cartesian coordinate system is named after him, allowing reference to a point in space as a set of numbers, and allowing algebraic equations to be expressed as geometric shapes in a two-dimensional coordinate system. He is credited as the father of analytical geometry, the bridge between algebra and geometry, crucial to the discovery of infinitesimal calculus and analysis. Descartes was also one of the key figures in the Scientific Revolution and has been described as an example of genius. He has been dubbed the 'Father of Modern Philosophy'. His Meditations on First Philosophy continues to be a standard text at most university philosophy departments.
On March 26, 1516, Swiss naturalist and bibliographer Conrad Gessner was born. His five-volume Historiae animalium (1551–1558) is considered the beginning of modern zoology, and the flowering plant genus Gesneria is named after him. He is considered as one of the most important natural scientists of Switzerland and was sometimes referred to as the 'German Pliny'.
On February 22, 1788, famous and most influential German philosopher Arthur Schopenhauer was born. He is best known for his book, The World as Will and Representation, in which he claimed that our world is driven by a continually dissatisfied will, continually seeking satisfaction.
On February 17, 1600, Domonican friar, philosopher, mathematician and astronomer Giordano Bruno was burned on the stake after the Roman Inquisition found him guilty of heresy. His cosmological theories went beyond the Copernican model in proposing that the Sun was essentially a star, and moreover, that the universe contained an infinite number of inhabited worlds populated by other intelligent beings.
On December 4, 1679, Thomas Hobbes passed away. The philosopher of the Age of Enlightenment and the political theorist of the Absolutism is probably best known for his 1651 book Leviathan that established the foundation for most of Western political philosophy from the perspective of social contract theory.
On November 21, 1694, François-Marie Arouet was born, known by his nom de plume Voltaire, French philosopher during the Age of Enlightenment, re-known by his wits, prolific writer of novels, poems, essays, and letters, and dear friend of Prussian king Frederick the Great.