Rationalism is a doctrine that prioritizes reason over emotion. If you're scared of the dark and convinced there's a monster in your closet, your parents will beg you to be rational, and rely on what you know (empty closet) instead of what your fear (monster!).

French philosopher René Descartes, who wrote "I think therefore I am," is considered the father of rationalism. He believed that eternal truths can only be discovered and tested through reason. The "scientific method" is one of rationalism's great gifts to mankind––if something cannot be proven through a repeatable experiment, you do not consider it to be true.

Definitions of rationalism

n the doctrine that reason is the right basis for regulating conduct

Type of:
doctrine, ism, philosophical system, philosophy, school of thought
a belief (or system of beliefs) accepted as authoritative by some group or school

n (philosophy) the doctrine that knowledge is acquired by reason without resort to experience

Type of:
philosophical doctrine, philosophical theory
a doctrine accepted by adherents to a philosophy

n the theological doctrine that human reason rather than divine revelation establishes religious truth

deism, free thought
the form of theological rationalism that believes in God on the basis of reason without reference to revelation
Type of:
theological doctrine
the doctrine of a religious group

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