Rudolf Carnap and his colleagues in the Vienna Circle added very little of lasting value to either science or philosophy with their strong ideas in the philosophy of science. They believed that both subjects were reducible to language and logic. Ludwig Wittgenstein had set the project for the Vienna Circle in the Tractatus Logico-Philosophicus.
4.11 The totality of true propositions is the whole of natural science (or the whole corpus of the natural sciences)In his 1928 book Der Logische Aufbau der Welt, and especially his 1934 work Logische Syntax der Sprache (published in 1937 as The Logical Syntax of Language), Carnap thought that he completed the Wittgenstein project, but with significant differences from some of Wittgenstein's views in the Tractatus. The logical syntax of a language is a set of formal rules. They have nothing to do with the "meaning of the symbols (for example, the words) or the sequence of expressions (the sentences), but simply and solely to the kinds and order of the symbols from which the expressions are constructed." As logical empiricists or positivists, they were committed to minimal "interpretations" of "reality" itself. Their goal was a "unified science" built up from pointer readings, from physical "observables." They were inspired by the early work on relativity by Albert Einstein, who had been inspired by Ernst Mach's positivism and opposition to metaphysics.
Limiting physics to observables, instead of a preconception about how reality must be, was behind Werner Heisenberg's uncertainty principle. Thus we can observe the spectral lines emitted by electrons when they jump from one orbit to another, but we cannot observe the orbiting electrons themselves.
For Carnap, a causal law was simply the fact that events are predictable. Quantum uncertainty put limits on that predictability, and some physicists spoke loosely of "the failure of the principle of causality only because it has become impossible to make predictions with any desired degree of accuracy."
Carnap and the End of Metaphysics