Logical positivism
Instrumentalism became popular among physicists around the turn of the 20th century, after which logical positivism defined the field for several decades. Logical positivism accepts only testable statements as meaningful, rejects metaphysical interpretations, and embraces verificationism (a set of theories of knowledge that combines logicism, empiricism, and linguistics to ground philosophy on a basis consistent with examples from the empirical sciences). Seeking to overhaul all of philosophy and convert it to a new "scientific philosophy", the Berlin Circle and the Vienna Circle propounded logical positivism in the late 1920s.