The unmitigated failure of A. J. Ayer’s significance criterion in Language, Truth, and Logic reveals the fundamental folly of any attempt to formulate such a criterion. This is the familiar, critical appraisal of the historically contentious search for a precise litmus test that would distinguish statements empirical observation bears on from others. But neither the specific indictment of Ayer’s efforts nor the negative assessment of the general project should be accepted. 

Ayer’s original proposals were certainly inadequate, but it is far from clear the deficiencies cannot be remedied by well-motivated amendments. Alonzo Church’s decisive criticism was an early volley in a more than half-century exchange between proponents and detractors. Calling that series of conceptually well-motivated and technically sophisticated maneuvers “the sorry history of unintuitive and ineffective patches,” (Lewis 1988) is neither charitable nor accurate.

Bio: James Justus is Professor of Philosophy at Florida State University. His research interests include philosophy of science (esp. biology), history of analytic philosophy, environmental philosophy, formal epistemology, philosophical methodology, and philosophy of mathematics.