For ten points, identify this premier group of logical positivists based in Austria's capital.
In 1991, an Institute with the same name as this group was founded by Friedrich Stadler, its best contemporary explicator. A.J. Ayer popularized its work in Britain and Quine briefly visited its members. It was founded by Hahn, Frank, and Neuruth in 1922 and many early meetings were discussion of the Tractatus Logico-Philosophicus. Primarily concerned with the unification of science and the verifiability principle, its prominent members included Moritz Schlick and Rudolf Carnap. For ten points, identify this premier group of logical positivists based in Austria's capital.
In 1991, an Institute with the same name as this group was founded by Friedrich Stadler, its best contemporary explicator.
Vienna Circle (or Wiener Kreis)