 Logical positivism was briefly in vogue in the 1930s but quickly ran into intractable difficulties. That something is seriously awry can be seen by subjecting the verification principle to its own standards: it is itself neither empirically verifiable nor analytically true, so literally meaningless according to its own criterion. Ayer exacerbated this problem by exaggerating the predicament of statements that failed to satisfy this principle, sometimes characterising them as “nonsense”. However, the central reason for the theory’s collapse was the failure to come up with a workable version of the verification principle (see MacDonald 2010 for a review). Ayer was unable to find a happy medium between a strict formulation that renders statements of scientific theory unverifiable and a lax formulation that allows any statement to be verifiable.