Logical Positivism

   The Question of the Validity and Justification of Metaphysics

   There have been many opponents of metaphysics from the Greek sceptics to the empiricists of the nineteenth century. Criticisms of very diverse kinds have been set forth. Many have declared that the doctrine of metaphysics is false, since it contradicts our empirical knowledge. Others have believed it to be uncertain, on the ground that its problems transcend the limits of human knowledge. Many anti-metaphysicians have declared that occupation with metaphysical questions is sterile. Whether or not these questions can be answered, it is at any rate unnecessary to worry about them; let us devote ourselves entirely to the practical tasks which confront active men every day of their lives!

   The development of modern logic has made it possible to give a new and sharper answer to the question of the validity and justification of metaphysics. The researchers of applied logic or the theory of knowledge, which aim at clarifying the cognitive content of scientific statements and thereby the meanings of the terms that occur in the statements, by means of logical analysis, lead to a positive and to a negative result. The positive result is worked out in the domain of empirical science; the various concepts of the various branches of science are clarified; their formal, logical and epistemological connections are made explicit.

   In the domain of metaphysics, including all philosophy of value and normative theory, logical analysis yields the negative result that the alleged statements in this domain are entirely meaningless. Therewith a radical elimination of metaphysics is attained, which was not yet possible from the earlier anti-metaphysical standpoints. (Carnap, 1959, p. 60)