From the 1400's to the early 1600's, philosophers turned their attention to the way things happen on earth, and the way to seek truth through reason.    Scientists of the era were successful in their methods of investigation.    Mathematics grew in importance with the findings of Nicolaus Copernicus and Sir Isaac Newton.
    Copernicus, Galileo, and Johannes Kepler laid the foundation on which Newton later built his great system of the world.

• Nicolaus Copernicus, 1473-1543, was a Polish astronomer who advanced the theory that the earth and other planets revolve around the sun, disrupting the Ptolemaic system of astronomy.
• Galileo Galilei 1564-1642, was an Italian astronomer and physicist.    The first to use a telescope to study the stars (1610), he was an outspoken advocate of Copernicus's theory that the sun forms the center of the universe, which led to his persecution and imprisonment by the Inquisition (1633).    He made measurement and experiment the source of all truth.
• Johannes Kepler 1571-1630, was a German astronomer and mathematician.    Considered the founder of modern astronomy, he formulated three laws to clarify the theory that the planets revolve around the sun.
• Francis Bacon first Baron Verulam and Viscount Saint Albans from 1561-1626.    English philosopher, essayist, courtier, jurist, and statesman.    His writings include The Advancement of Learning (1605) and the Novum Organum (1620), in which he proposed a theory of scientific knowledge based on observation and experiment that came to be known as the inductive method.
• Sir Isaac Newton 1642-1727, was a English mathematician and scientist who invented differential calculus and formulated the theories of universal gravitation, terrestrial mechanics, and color.    His treatise on gravitation, presented in Principia Mathematica (1687), was supposedly inspired by the sight of a falling apple, and became the basis for the science of physics.    Newton described the world as a giant machine.    He was also a student of alchemy, and made many alchemical experiments.    He spent a great deal of his time on questions of theology and Biblical chronology.
      Other Renaissance Philosophers:
• Niccolò Machiavelli 1469-1527, an Italian political theorist whose book The Prince (1513) describes the achievement and maintenance of power by a determined ruler indifferent to moral considerations.    He stressed reason rather than morality in politics to achieve nationalistic policies.
• Michel Eyquem de Montaigne 1533-1592, a French essayist whose discursive, lively personal essays are considered the highest expression of 16th-century French prose.    He expressed skepticism that reason could find truth and urged a return to simplicity and nature, away from the corruption of civilization.
• Jean Jacques Rousseau 1712-1778, a French philosopher and writer who held that humanity is essentially good but corrupted by society.    His written works include The Social Contract and the novel Émile (both 1762).    He developed this idea from Jean Bodin who introduced that the state is based on a social contact (a precursor to Democracy).
      Other points of interest:
  
• Jakob Boehme or Boehm or Bohme, born 1575-1624, was a German theosophist and mystic whose works, including Mysterium Magnum (1623), describe evil as a necessary antithesis to good.    He is considered the founder of modern theosophy.