A worldview that relies on reason or logic as the main source of knowledge. Mathematics is the prime example of rationalism. This worldview has a long history in the West, Middle East and beyond, from Greek philosophers Pythagoras (570–495 BCE), Socrates (c. 470–399 BCE), Plato (427–347 BCE), Persian philosopher Ibn Sina aka Avicenna (980–1037 CE), Morocco- and Egypt-based Jewish philosopher Moses ben Maimon aka Maimonides (1138–1204), French philosopher René Descartes (1596–1650), German philosopher GWF Hegel (1770–1831), American philosophers Josiah Royce (1855–1916) and Laurence BonJour (b. 1943). The term ‘rationalist’ emerged in the 16th century (initially in France, in French) in contrast to ’empiricist’, though rationalism and empiricism are broadly similar and not easily parsed. In rough terms, rationalists believe knowledge can be gained through thinking, whereas empiricists believe all our knowledge arrives via the senses. Rationalism was the major foundational philosophy of the mainly 18th century European Enlightenment (aka the Age of Reason).