demarcation the line separating empirical science from mathematics and logic, from metaphysics, and from pseudoscience. Science traditionally was supposed to rely on induction, the formal disciplines (including metaphysics) on deduction. In the verifiability criterion, the logical positivists identified the demarcation of empirical science from metaphysics with the demarcation of the cognitively meaningful from the meaningless, classifying metaphysics as gibberish, and logic and mathematics, more charitably, as without sense. Noting that, because induction is invalid, the theories of empirical science are unverifiable, Popper proposed falsifiability as their distinguishing characteristic, and remarked that some metaphysical doctrines, such as atomism, are obviously meaningful. It is now recognized that science is suffused with metaphysical ideas, and Popper’s criterion is therefore perhaps a (rather rough) criterion of demarcation of the empirical from the nonempirical rather than of the scientific from the non-scientific. It repudiates the unnecessary task of demarcating the cognitively meaningful from the cognitively meaningless. See also FALSIFIA — BILITY, INDUCTION , MEANING , METAPHYSICS , POPPER , VERIFIABILITY. D.W.M.