Logical Positivism is Sound

What Logical Positivism IsThe particular formulation of Logical Positivism I will defend is that of its most prominent advocate, A. J. Ayer, though support will be found in Wittgenstein, who held essentially a positivistic attitude.Logical Positivism divides propositions into two categories: cognitive and non-cognitive. Cognitive propositions have sense; they have meaning. Non-cognitive propositions are senseless. Cognitive propositions are divided further into two types: empirical and analytic. Note: Positivism denies the idea of the synthetic a priori - if a proposition is a priori, it must be verifiable logically, not empirically, and thus cannot be contingent on any state of the world which logic Any proposition which is neither empirical nor analytic has no sense, and therefore can be neither true or false - it must be discarded out-of-hand.The Verification Principle For a proposition to have any meaning, it must picture something about the world (for, if not, on what else can meaning be based?). Propositions are, then, representations of the world, and are true or false depending on the accuracy of the representation.Since representation requires a means of representation, and thus a common ground between it and that which is being represented, this means of representation supersedes any particular picture. Wittgenstein explains:"The picture represents its object from without (its standpoint is its form of representation), therefore the picture represents its object rightly or falsely.But the picture cannot place itself outside of its form of representation.What every picture, of whatever form, must have in common with reality in order to be able to represent it at all"rightly or falsely"is the logical form, that is, the form of reality.What the picture represents is its sense.In the agreement or disagreement of its sense with reality, its truth or falsity consists. In order to discover whether the picture is true or false we must compare it with realityIt cannot be discovered from the picture alone whether it is true or false." [Wittgenstein, Tractatus Logico-Philosophicus]The best known formulation of this is the Verification Principle: the meaning of a proposition is its means of verification.This is clear: if a proposition has meaning, it must represent the world, and therefore derives its truth value from this representation. If no representation takes place, no meaning exists. If a proposition's truth or falsity would correspond to two states of the world which are the same in every way, the proposition represents nothing in the world, and has no sense.Positivists take an uncompromising stance against metaphysics and the mystical for this reason; *any* proposition which is not verifiable (which one cannot compare to reality) or purely logical is nonsense. Either it is purely logical, in which case it says nothing particular, or deals with matters-of-fact; no alternative is possible.What would the world look like if it were true that murder is immoral? One cannot say. What would the world look like if there were something beyond it? One cannot say. Positivists echo Hume: "If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion."Wittgenstein makes clear the absurdity of positing things outside logic:"Logic pervades the world: the limits of the world are also its limits. So we cannot say in logic, "The world has this in it, and this, but not that." For that would appear to presuppose that we were excluding certain possibilities, and this cannot be the case, since it would require that logic should go beyond the limits of the world; for only in that way could it view those limits from the other side as well. We cannot think what we cannot think; so what we cannot think we cannot say either." [Wittgenstein, Tractatus Logico-Philosophicus, 5.61]And, with that, metaphysics has been removed.