Confirmational holism is the claim that scientific theories are confirmed or disconfirmed as a whole. Thus the framework of a theory (formal conceptual scheme) is just as open to revision as the "content" of the theory. The aphorism that Quine uses is: theories face the tribunal of experience as a whole. This idea is problematic for the analytic-synthetic distinction because such a distinction supposes that some facts are true of language alone, but if conceptual scheme is as open to revision as synthetic content, then there can be no plausible distinction between framework and content, hence no distinction between the analytic and the synthetic. Also called the Quine-Duhem thesis

One upshot of confirmational holism is the underdetermination of theories: if all theories (and the propositions derived from them) of what exists are not sufficiently determined by empirical data (data, sensory-data, evidence); each theory with its interpretation of the evidence is equally justifiable. Thus, the Greek's worldview of Homeric gods is as credible as the physicists' world of electromagnetic waves. Quine later argued for Ontological Relativity, that our ordinary talk of objects suffers from the same underdetermination and thus does not properly refer to objects.

While underdetermination does not invalidate the principle of falsifiability first presented by Karl Popper, Popper himself acknowledged that continual ad hoc modification of a theory provides a means for a theory to avoid being falsified. In this respect, the principle of parsimony, or Occam's Razor, plays a role. This principle presupposes that between multiple theories explaining the same phenomenon, the simplest theory--in this case, the one that is least susceptible to continual ad hoc modification--is to be preferred.

References

• W.V. Quine. 1951. Two Dogmas of Empiricism
• W.V. Quine. 1960. Word and Object
• W. V. Quine. 1969 Ontological Relativity
• D. Davidson. 1975. On the Very Idea of Conceptual Scheme