In philosophy generally, empiricism is a theory of knowledge emphasizing the role of experience.
In the philosophy of science, empiricism is a theory of knowledge which emphasizes those aspects of scientific knowledge that are closely related to experience, especially as formed through deliberate experimental arrangements.
It is a fundamental requirement of scientific method that all hypotheses and theories must be tested against observations of the natural world, rather than resting solely on a priori reasoning, intuition, or revelation.
Hence, science is considered to be methodologically empirical in nature.
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