Science, Philosophy of

Logical Positivism

Logical positivism developed from the ideas of positivism, epistemology, and mathematical logic. Positivism was derived from the work of French philosopher August Comte (1798–1857), who hypothesized that human culture evolved through three stages:theological, metaphysical, and positive. In the theological stage, humans understand nature through religious superstition and magic. During the metaphysical stage, magic and religion are replaced by[Page 2063]impersonal but unobservable forces. The final positivist stage, according to Comte, is where understanding truly lies: humans rely on observation and experiment to understand nature. Positivists were skeptical of metaphysics in general and many theories involving phenomena that were not directly observable. Logical positivists, however, through the work of Gottlob Frege(1848–1925) and Bertrand Russell (1872–1970), added mathematical logic to the positivist philosophy. Mathematical logic is subject-neutral and, through the use of symbolic rather than linguistic terms, makes it possible to analyze objectively all kinds of concepts.

Logical positivists believe that all the events that take place in the natural world are controlled by the laws of nature. These laws can be determined through the observation of consistencies in the relationships between observable phenomena and make possible the explanation of natural phenomena. They developed the verifiability principle: a statement is meaningful if and only if it can be proven true or false through experience. These statements are proven true or false through mathematical logic, written as material conditionals (mathematical if-then statements). Logical positivists originally required that every element of every scientific theory must be expressed in precise mathematical ways, using definitions called correspondence-rules. These correspondence-rules explain how the nonobservable elements of the theory make a difference to observational experience. If there is no observable difference in result between a theory that includes an unobservable element X and one that doesn't, then, say the logical positivists, there is no evidence that element X is present at all. The correspondence-rule requirement made it necessary to account for every element in the theory in a way that could be verifiable through observation. Therefore, one of the central issues of the positivist approach is the difference between observational terms and theoretical terms.

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