 Carnap’s life-long quest to explicate the distinction between statements that genuinely convey something and empty verbiage that only purports to say something (metaphysics) began with Wittgenstein’s Tractatus, the Vienna Circle’s provisional starting point. The Circle interpreted Wittgenstein as requiring what Carnap later called a “molecular” language, by which he meant a language that permitted only finitely restricted quantification. This posed an obvious problem in that scientific theories, the very paradigm of what the Circle regarded as proper (non-metaphysical) knowledge, nearly all contain unrestricted universal quantifiers and thus range, in principle, over an infinite number of instances. As Carnap already acknowledged in his first writings on the subject, well before Popper appeared on the scene, this meant that theories could not, strictly speaking, be verified; they could only be confirmed up to a certain confidence level, or disconfirmed (e.g., Carnap 1926: 7–9).