Criterion of meaningfulness associated with logical positivism and the Vienna Circle .
Moritz Schlick's formulation "The meaning of a [declarative sentence] is the method of its verification" was close to the view held in pragmatism , and later in operationalism , that an assertion has factual meaning only if there is a difference in principle, open to test by observation, between the affirmation and the denial of the assertion. Thus, the statements of ethics, metaphysics, religion, and aesthetics were held to be meaningless. The verifiability criterion of meaningfulness was in part inspired by Albert Einstein 's abandonment of the ether hypothesis and the notion of absolute simultaneity.