Rationalism is a philosophical viewpoint asserting that reason is the primary source and test of knowledge, often prioritizing intellectual and deductive truth over sensory experience, faith, or tradition. During the Enlightenment, this position, sometimes equated with innatism, stood in opposition to empiricism. Key rationalists like René Descartes argued that knowledge is largely innate and that the intellect can directly grasp logical and fundamental truths in areas such as mathematics and ethics, making empirical proof sometimes unnecessary.
This "Continental Rationalism," particularly strong in Europe, saw thinkers such as Baruch Spinoza and Gottfried Leibniz propose that, in principle, all knowledge could be deductively derived from foundational basic principles through reason alone, much like geometric axioms. These philosophers displayed profound confidence in the power of reason, believing it capable of revealing significant truths independently of sense experience, thereby profoundly influencing Western philosophy.