Rationalism is the belief that reason is the best or most reliable means of acquiring knowledge. It is often used in contrast to empiricism, the belief that knowledge comes from experience.Rationalism is used in many different fields, such as philosophy, science, and politics. In philosophy, rationalism is used to contrast with empiricism and other epistemological approaches. For example, René Descartes famously argued that knowledge could be acquired through reason alone, without the need for experience. In science, rationalism is often used to refer to the scientific method, which relies on reason and observation to acquire knowledge about the natural world. In politics, rationalism is sometimes used to refer to the belief that reason, rather than passion or emotion, should guide political decision-making.