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..

Article Source