Logical positivism is a school of thought that contends that only those statements that are supported with empirical research are meaningful and valid. This movement grew in popularity in the 1920s and 1930s, a time when scientific research and general fascination with scientific experimentation was becoming increasingly common. Ernst Mach and Ludwig Wittgenstein were some of the most prominent European logical positivists; they were some of several researchers that were forced to leave Europe and spread their ideas to other parts of the world as a result of the political climate on the continent at this point in history. The root of logical positivism is known as verificationism, or the idea that only those things that can be verified as either true or false are meaningful.
Logical positivism rejects the principles of metaphysics, or the study of existence. The tenets of this philosophical study are not necessarily wrong, but because they cannot be definitively proven, they simply have no meaning. Logical positivism also rejects synthetic a priori propositions – as they cannot be proven – in favor of analytic statements which are provable simply by their definitions. Additionally, language is defined strictly by how it is used in language, incorporating the thoughts that are associated with a given word. Ultimately, logical positivism is based in the idea that all knowledge can be broken down into a common language of scientific understanding; it was the hope of prominent logical positivists that increasing parts of traditional language would be replaced with this standard language of science.