Coherence Measure Based on Average Use of Formulas

Coherence is a positive virtue of theories, and its importance in theory construction is beyond debate. Unfortunately, however, a rigorous and computable definition of coherence is conspicuously lacking in the literature. This paper attempts to remedy this situation by formalising this notion of coherence and suggesting a measure. Roughly speaking, we suggest that a theory is coherent to the degree that its members (read formulas) are required to account for the intended class of observations. This approach is motivated by Bonjour’s account of coherence. We also generalise this notion of coherence to work in the context of a potentially infinite long sequence of observations.