Logical Positivism

Conceptual Overview

The essential feature of logical positivism is a strict principle of scientific verifiability concerning all statements about ideas or real phenomena. Acceptable proof may be logical or empirical, hence the label logical positivism. Scientifically meaningful statements must be either logically true (i.e., analytic) or empirically verifiable (i.e., synthetic). An analytic statement about an idea or concept can be demonstrated logically (i.e., through a priori reasoning) to be true or false independently of any empirical experience. The Latin term a priori means deductive reasoning from cause to effect based on theory. For example, in plane geometry, a line can be defined as the distance between two points. This definition is analytically true. A synthetic or empirical statement about real phenomena must be verified by observation or other sensory experience. The Latin term a posteriori means inductive reasoning from effect to cause based on observation or experience. For example, by verifiable observation, the moon rotates about the earth, which rotates about the sun.

Logical positivism asserts that any other statements, being neither analytically true nor empirically verifiable, are meaningless. Metaphysics, theology, and ethics therefore must fall within this meaningless category. Today's philosophers believe that critical and speculative inquiries can prove useful independent of strict scientific proof.

Logical positivism also has been called or treated as synonymous with variously consistent empiricism, logical empiricism, logical neopositivism, rational empiricism, and scientific empiricism. This variable terminology reflects intellectual roots in both 18th century British empiricism and the positivism of the 19th century French sociologist Auguste Comte. British empiricism asserted that all knowledge must be experiential and cannot come from reason alone. Logical positivism did not accept this position, as there can be logical arguments. Comte applied scientific observation and experimentation (i.e., positivism) to a new science of sociology aimed at reform of society along strictly scientific principles. Comte viewed sociology as a third and scientific phase of social development beyond earlier, outmoded theological and metaphysical stages; it absorbed philosophy and all other sciences. Hence logical positivism is neopositivism but not strictly pure empiricism on the British model. Logical positivism asserts scientific unification but attempts to combine deductive theory and inductive observation.

In 1931, Albert E. Blumberg and Herbert Feigl gave the name logical positivism to the set of ideas advanced over time by what became known as the Vienna Circle. The logical positivism movement began in 1907 when a mathematician, an economist, [Page 830]and a physicist at the University of Vienna began informally to discuss philosophy of science. They were reacting to strongly empiricist views, akin to British empiricism and Comte, of the experimental physicist Ernst Mach, who argued that science describes experience. These academics felt that Mach, who was also antimetaphysical in his views, did not give sufficient importance to mathematics, logic, and theoretical physics. Modern physics combines mathematical theorizing and empirical verification. This Vienna group looked to the new positivism of French mathematician Henri Poincaré. From 1922, when the group stimulated his invitation to join the University of Vienna, a larger Vienna circle organized around Moritz Schlick. In 1926, Rudolf Carnap joined the university and became the leading exponent of the circle's views. Ayer stimulated appreciation for the Vienna Circle in the English-speaking world through his book Language, Truth and Logic (1936). The title succinctly linked the logical positivism of the Vienna Circle (truth and logic) with the language philosophy of Ludwig Wittgenstein and George E. Moore.

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