Rudolf Carnap, largely known for his development of logical empiricism, was born on May 18, 1891 in Ronsdorf, Germany. Although his parents were profoundly Protestant, their tolerant views allowed Carnap to make a smooth transition into the more pantheistic and scientific ideology he developed later in his life. Between 1910-14, he studied mathematics, physics and philosophy at both the University of Jena and Freiburg im Breisburg. In Jena he was greatly influenced by the mathematician and logician, Gottlob Frege. His studies though, were interrupted by his service in the military. After World War I, he returned to Jena to finish his doctoral degree in philosophy which he completed in 1921. He then conducted personal research for several years on logic and the foundations of physics. This research lasted until 1926, when Moritz Schlick invited him to the University of Vienna as a member of the faculty and the Vienna Circle. This was a group founded by Schlick as an interdisciplinary forum for professors to discuss philosophical issues. Carnap became a vital member of this group and out of their discussions, the theory of logical positivism began to take shape.

Logical positivism (or logical empiricism) was both a result of his influences in Vienna, and Carnap’s desire to create a new philosophy that completely severed all ties with metaphysical ideology. As an advocate of exploring and sharing ideas with his fellow colleagues, Carnap found the Vienna Circle to be an especially productive environment. This sharing of intellectual ideas expanded beyond Vienna and into other cities such as Berlin, where he met the empiricist Hans Reichenbach. Together they founded the journal Erkenntnis (1930-40), as a forum for the new ideas developing in scientific philosophy. The Vienna Circle conversations, especially with Moritz Schlick, helped Carnap develop his ideas of logical empiricism through an analysis of the language of science, specifically in the construction of formal and logical systems. He was especially interested in the areas of semantics and inductive logic. Although Carnap was influenced by Ludwig Wittgenstein’s ideas of truth in logical conceptions, their philosophical foundations diverged as Wittgenstein seemed more interested in individual and aesthetic conceptions of philosophy, while Carnap focused on a more scientific philosophy. He pursued this area of research by asserting that sentences and terms, those words and ideas that humans use initially in their observations and descriptions of the world, could be reduced to a second empirical level of thought. This is detailed in his work The Logical Structure of the World (Der logische Aufbau der Welt). Later, he furthered this idea by arguing that these empirical statements could then be tested and described in the language of physics. He felt this concept of physicalistic materialism could be used in both the physical and social sciences. Carnap eventually left Vienna and in 1931, took the position of Professor of Natural Philosophy in Prague, where he continued to develop his conceptions of empiricism. In 1935, as the threat of Nazism grew intolerable for Carnap, he left Prague, opting to move to the United States to continue his work.

In the United States, Carnap first served on the faculty of the University of Chicago. He stayed there until 1952, with the exception of the 1940-41 academic year, where he served as a visiting professor at Harvard University. Here he was surrounded by intellectuals such as the British philosopher Bertrand Russell, who was one of Carnap’s greatest philosophical influences. Chicago proved to provide a rich intellectual community for Carnap. With sociologist Otto Neurath and philosopher Charles Morris, he founded the publication, "International Encyclopedia of Unified Science." This publication focused on issues concerning the philosophy of science, in areas such as mathematics and certain branches of empirical science. After 1945, he began to rigorously pursue a formal system of inductive logic, writing the book, Logical Foundations in Probability in 1950. Here he writes in depth how probability can be used when imparting evidence upon a proposed hypothesis. After leaving Chicago he continued to work with probability throughout his service at the Institute for Advance Study in Princeton (1952-1954). Carnap then took a professorship at the University of California, Los Angeles; during this time and until his death in 1970 he continued to further his theory of inductive logic.



-Christina Weber