A scientific theory is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method , using accepted protocols of observation , measurement, and evaluation of results. Where possible, theories are tested under controlled conditions in an experiment . [1] [2] In circumstances not amenable to experimental testing, theories are evaluated through principles of abductive reasoning . Established scientific theories have withstood rigorous scrutiny and embody scientific knowledge . [3]
