A competing theory of meaning is true. 1
This is relevant because these theories of meaning are not compatible with the verificationist theory of meaning.
Verificationism is self-refuting. (After all, the statement that “only observation-affecting statements are meaningful”, is not an observation-affecting statement).1 This is relevant because self-refuting statements are false.
Universal generalizations (i.e. inferences to natural laws) cannot be verified by experience.1 (For example, no matter how many ravens are observed to be black, one cannot thereby confirm that all ravens are black. The same goes for the exemplification of laws like gravity.) This is relevant because universal generalizations, like “all ravens are black,” are perfectly meaningful.
• The Philosophy of Science: An Encyclopedia, Vol 1: A-M: “Wittgenstein's principle of verifiability posed fairly obvious problems in any scientific context. No universal generalization can ever be verified. Perhaps independently, Karl Popper perceived the same problem... This led him to replace the requirement of verifiability with that of falsifiability, though only as a criterion to demarcate science from metaphysics and not as one to be able also used to demarcate meaningful from meaningless claims.” [The “Rudolf Carnap” entry, eds. Sahotra Sarkar, Jessica Pfeifer (Routledge, 2005), 83.]
• The Stanford Encyclopedia of Philosophy: “In a series of studies about cognitive significance and empirical testability, he demonstrated that the verifiability criterion implies that existential generalizations are meaningful, but that universal generalizations are not, even though they include general laws, the principal objects of scientific discovery. Hypotheses about relative frequencies in finite sequences are meaningful, but hypotheses concerning limits in infinite sequences are not. The verifiability criterion thus imposed a standard that was too strong to accommodate the characteristic claims of science and was not justifiable.” [James Fetzer, “Carl Hempel”, in Edward N Zalta, ed, The Stanford Encyclopedia of Philosophy (Spring 2013)]
Truths about logic and math are neither true-by-definition nor empirically verifiable.1 This is relevant because truths of logic and math are meaningful.