Rudolf Carnap

Philosopher

  • Born: May 18, 1891
  • Birthplace: Ronsdorf, Germany
  • Died: September 14, 1970
  • Place of death: Santa Monica, California

German-born American philosopher

Carnap is recognized as a leading figure in the philosophy of logical positivism and made significant contributions to logic, the theory of probability, the philosophy of science, and linguistic analysis.

Areas of achievement Philosophy, mathematics

Early Life

Rudolf Carnap (KAHR-nap) was born in Ronsdorf in northwestern Germany to deeply religious parents who did not want to expose their children to secular influences. Consequently, both Rudolf and his sister were educated by their mother at home. His father died when Rudolf was seven years old, and his mother continued to supervise his education until he left for the Universities of Jena and Freiburg in 1910. For four years, Carnap studied physics, philosophy, and mathematics. While studying at Jena, Carnap attended the lectures of Gottlob Frege, widely acknowledged as the most eminent logician of his time. Frege deeply influenced Carnap’s future work, although at that moment, Carnap’s interest lay in the physics of electrons. Carnap began his doctoral dissertation in physics when World War I began. He spent three years at the front and, in 1917, was transferred to Berlin to work on developing wireless communication for the army. For Carnap, the period of the war created an awareness of his pacifism and the irrationality of violent human conflict, and confirmed his belief in the values of rationality and science.

Carnap returned to philosophy in 1919 and at the same time encountered the works of Bertrand Russell. Frege had earlier sparked an interest in logic, and now Russell renewed that interest. The idea that symbols could take the place of sentences and that sentences operate with each other in a limited number of ways led Carnap to write a dissertation on an area that bordered both philosophy and physics. In 1921, he completed his work and received his Ph.D. from Jena with a thesis that compared the concepts of space used in physics, mathematics, and philosophy.

For several years, Carnap was content to work independently in areas of logic and physics. He wrote a number of articles on space, time, and causality, and began work on a textbook on symbolic logic. In 1926, he was invited to teach at the University of Vienna, and this turned out to be the decisive step toward an important career in philosophy.

Life’s Work

When Carnap was invited to become an instructor at the University of Vienna in 1926, he was ready to begin a unique exploration of one philosophical area. Moritz Schlick, who had arranged the invitation to Vienna, also formed the Vienna Circle that year by bringing together philosophers, mathematicians, linguists, and other scholars. Schlick wanted to develop a system of philosophy in which all statements could be rigorously verified by logic. Carnap became a leading member of the circle and from their discussions shared in the initial ideas of logical positivism or logical empiricism.

Before going to Vienna, Carnap had begun to organize his interest in mathematical logic. Frege recommended a reading of Principia Mathematica (1910-1913), a masterful work on logic by Russell and Alfred North Whitehead that attempted to derive all of mathematics from a set of premises. Deeply influenced by this work, Carnap in 1924 completed a first draft of a textbook on mathematical logic entitled Abriss der Logistik mit besonderer Berücksichtigung der Relationstheorie und ihrer Anwendungen. It was first published in 1929 and later translated into English from a considerably different version in 1958 as Introduction to Symbolic Logic and Its Applications. Carnap arrived in Vienna in 1926 and began his duties as an instructor at the university. During the next five years, he actively participated in conversation with the members of the Vienna Circle, taught, and wrote.

During this period in Vienna, Carnap became one of the leading advocates for a philosophical position called logical positivism or logical empiricism. This school of thought synthesized the empiricism of David Hume and, combined with the revolution in modern physics, attempted to create a precise and rigorous philosophy that claimed all human knowledge originated from immediate experience. For Carnap, the culmination of these five years was the publication in 1928 of Der Logische Aufbau der Welt (The Logical Structure of the World, 1967). Carnap organized all the objects of the world into four main types: sociocultural objects, others’ minds, physical objects, and personal experiences. By accepting the human ability to remember similarities, Carnap built a system of knowledge where comparison between similarities would lead to the creation of a temporal order. Carnap believed that a person’s experience at any given moment was created from a series of elements and that these series were constructed over time. Those remembered similarities provided the initial store of experiences that led to the definition of a person, perception, and the world.

In 1930, Carnap and Hans Reichenbach published a periodical called Erkenntnis for the purpose of promoting and discussing the issues of the Vienna Circle. Published for ten years, this journal contains central ideas of the school as well as controversies and points of difference. In 1931, Carnap accepted the chair of natural philosophy at the German University in Prague, Czechoslovakia. While continuing his close relationship with the Vienna Circle, Carnap turned his attention more narrowly to problems of logic and language. This work resulted in the publication in 1934 of his second major work, Logische Syntax der Sprache (The Logical Syntax of Language, 1937). In this book, Carnap attempted to formulate the logical syntax of any language in terms of rules of formation and transformation. Also during the Prague period, Carnap moved away from the rigorous demands of his earlier empiricism, in which sentences that cannot be tested by observation were regarded as empirically meaningless. Carnap devised a means by which those sentences unable to be checked directly may be reduced in such a way as to be testable.

With the rise and threat of National Socialism in Germany, Carnap decided to leave Europe in December, 1935. On arrival in the United States, he received an appointment as professor of philosophy at the University of Chicago. He spent seventeen years at Chicago and, during this period, engaged in several revisions of Logical Syntax of Language and shared the editorial responsibilities over the publication of The International Encyclopedia of Unified Science (1938). The overall purpose of the encyclopedia was to unify scientific terms with a series of articles devoted to general problems in the philosophy of science and specific disciplines in science. In his own work, Carnap shifted his emphasis toward problems in semantics, which resulted in three books: Introduction to Semantics (1942), Formalization of Logic (1943), and Meaning and Necessity (1947). Although his concern with semantics was new, the problem for Carnap originated with his first work. He wanted to rid philosophy of metaphysics, or “pseudoproblems.” He believed that much of the difficulty in philosophy was the result of a misunderstanding or misuse of language. With an artificial language, set according to specific rules and regulations, he believed that it would be possible to communicate more directly and clearly. Along this same path, Carnap took an avid interest in artificial languages such as Esperanto and Interlingua.

After 1945, Carnap shifted to the final phase of his philosophical life and worked on problems of probability and introduction. The publication of his third great work, Logical Foundations of Probability (1950), was the result of this effort. The core of Carnap’s philosophy lay in the belief that the meaning of a sentence lay in its ability to be tested or verified. Although deductive logic was a well-defined and complete system, inductive logic was not. Carnap attacked the problem by the claim that a close parallel existed between inductive and deductive logic. Through the construction of a formal system of inductive logic, which corresponded to deductive logic, Carnap came to the conclusion that if the process of deduction was valid, then by implication so was the process of induction.

In 1952, Carnap received an appointment at the Institute for Advanced Study at Princeton. There he was freed from academic duties and devoted his time to research. On the death of Reichenbach in 1954, Carnap decided to accept the chair in philosophy at the University of California, Los Angeles, vacated by his friend. He remained there until his retirement in 1961. At Los Angeles and during his retirement, Carnap continued to work on various refinements of his philosophical interests. Carnap became an American citizen in 1941. He received a Rockefeller Fellowship in 1942 and was a Fellow of the American Academy of Arts and Science. He was awarded honorary doctorates from Harvard University (1936), the University of California (1963), the University of Michigan (1965), and the University of Oslo (1969). Carnap died in Santa Monica, California, in 1970.

Significance

Carnap enjoyed a long and productive intellectual life that spanned almost half a century. He brought together several major strands of Western philosophy, including the empiricism of Hume, which exerted a powerful influence throughout the nineteenth century, and blended this tradition with the revolutionary advances in modern logic developed during the early part of the twentieth century. During his formative years, he was influenced by several of the greatest thinkers of the twentieth century, including Russell, Frege, and Ludwig Wittgenstein. During his productive years, Carnap maintained an active dialogue with individuals from a variety of academic disciplines. He became the best-known member of the Vienna Circle and provided the seminal works that proved invaluable in creating a modern philosophy of science. In 1940-1941, when Carnap was a visiting professor at Harvard University, he became a part of a discussion group that included Russell, Alfred Tarski, and W. V. O. Quine. Students privy to those discussions must surely have been aware that they sat at the feet of intellectual giants.

At the beginning of his career, Carnap committed himself to the position that a viable empiricism needed to be wedded to logic. Although his original position was characterized by an unprecedented rigor, throughout his life he modified this position in favor of greater flexibility. Along with his contributions to probability, it could be said that he placed one cornerstone in the study of the philosophy of science.

Bibliography

Awodey, Steve, and Carsten Klein, eds. Carnap Brought Home: The View from Jena. Chicago: Open Court, 2004. A collection of essays analyzing various aspects of Carnap’s philosophy.

Ayer, Alfred Jules. Philosophy in the Twentieth Century. New York: Random House, 1982. This book covers the major philosophical developments in the twentieth century. Chapter 4 covers the beginning of the Vienna Circle, and the following chapter deals in some detail with Carnap’s contribution to logical positivism. Accessible to general readers.

‗‗‗‗‗‗‗, ed. Logical Positivism. Glencoe, Ill.: Free Press, 1959. A thorough and comprehensive review of the philosophy of logical positivism. There are lengthy sections on Carnap and on the central figures of the Vienna Circle.

Buck, Roger C., and Robert S. Cohen, eds. Boston Studies in the Philosophy of Science. Vol. 8. Dordrecht, the Netherlands: D. Reidel, 1971. A collection of articles written on the occasion of Carnap’s seventieth birthday. The subjects of these articles cover the range of Carnap’s life and philosophy: from personal qualities to his influences as a teacher to the quality of his philosophical thought.

Kraft, Viktor. The Vienna Circle, the Origin of Neo-Positivism: A Chapter in the History of Recent Philosophy. Translated by Arthur Pap. New York: Philosophical Library, 1953. This book is recognized as the standard work on the members of the Vienna Circle. Kraft covers in some detail the major contributors to the circle, and Carnap receives a significant amount of attention. A good place to begin.

Mayhall, C. Wayne. On Carnap. Belmont, Calif.: Wadsworth/Thomson Learning, 2002. A brief overview of Carnap’s philosophy designed to provide students an introduction to his ideas.

Passmore, John Arthur. A Hundred Years of Philosophy. Rev. ed. New York: Basic Books, 1967. Passmore’s book provides a very readable and comprehensive text for developments in philosophy. Although the section on Carnap is brief, logical positivism is described in language that is relatively easy to understand.

Schilpp, Paul Arthur, ed. The Philosophy of Rudolf Carnap. La Salle, Ill.: Open Court, 1963. An excellent source for an overview of Carnap’s philosophy. It is possible to pick and choose among the sections and critical essays and to gain some insight into how Carnap proceeded in his thinking. Contains a complete bibliography.

1901-1940: 1921: Wittgenstein Emerges as an Important Philosopher; 1922: First Meeting of the Vienna Circle; July, 1929-July, 1931: Gödel Proves Incompleteness-Inconsistency for Formal Systems.

1941-1970: 1962: Kuhn Explores Paradigm Shifts in Scientific Thought.