<P> Verificationism thus rejects as cognitively "meaningless" statements specific to entire fields such as metaphysics, spirituality, theology, ethics and aesthetics . Such statements may be meaningful in influencing emotions or behavior, but not in terms of truth value, information or factual content . Verificationism was a central thesis of logical positivism, a movement in analytic philosophy that emerged in the 1920s by the efforts of a group of philosophers who sought to unify philosophy and science under a common naturalistic theory of knowledge . </P> <P> Although verificationist principles of a general sort--grounding scientific theory in some verifiable experience--are found retrospectively even with the American pragmatist C.S. Peirce and with the French conventionalist Pierre Duhem who fostered instrumentalism, the vigorous program termed verificationism was launched by the logical positivists who, emerging from Berlin Circle and Vienna Circle in the 1920s, sought epistemology whereby philosophical discourse would be, in their perception, as authoritative and meaningful as empirical science . </P> <P> Logical positivists garnered the verifiability criterion of cognitive meaningfulness from young Ludwig Wittgenstein's philosophy of language posed in his 1921 book Tractatus, and, led by Bertrand Russell, sought to reformulate the analytic--synthetic distinction in a way that would reduce mathematics and logic to semantical conventions . This would be pivotal to verificationism, in that logic and mathematics would otherwise be classified as synthetic a priori knowledge and defined as "meaningless" under verificationism . </P> <P> Seeking grounding in such empiricism as of David Hume, Auguste Comte, and Ernst Mach--along with the positivism of the latter two--they borrowed some perspectives from Immanuel Kant, and found the exemplar of science to be Albert Einstein's general theory of relativity . </P>

What is the principle of verification what is wrong with it