unified science, in the philosophy of logical positivism, a doctrine holding that all sciences share the same language, laws, and method or at least one or two of these features. A unity-of-science movement arose in the Vienna Circle, a group of scientists and philosophers that met regularly in Vienna in the 1920s and ’30s and was associated in particular with Rudolf Carnap and Otto Neurath. Versions of the unity-of-science thesis are still supported by many contemporary philosophers of science.

The claim that all sciences share a common language may mean one of two things: (1) For the logical positivist, the claim often meant that all scientific terms could be restated as, or reduced to, a set of basic statements, or “protocol” sentences, describing immediate experience or perception. (2) More recently, unity of language has meant the reduction of all scientific terms to terms of physics.

The unity of law means that the laws of the various sciences are to be deduced from some set of fundamental laws, often thought to be those of physics.

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philosophy of science: Unification and reduction

Finally, the unity of method means that the procedures for testing and supporting statements in the various sciences are basically the same. The procedures of the populations biologist, for example, purportedly are fundamentally no different than those of the theoretical physicist.