The Habitual Horizon:

At the end of Frank Ramsey’s “General Propositions and Causality” ([1929b] 1990), he offers an enigmatic footnote that briefly describes his philosophy of science as a “forecasting theory”. What he means by this and by a “forecast” is unclear. However, elsewhere in his unpublished notes, he uses the term sporadically. An examination of those notes reveals the skeleton of a behavioral theory of mind. Ramsey held that all actions are at root driven by the sum total of a person’s dispositions or habits. These habits operate in an unconscious process that produces psychological expectations about the realization of desires. When those expectations are frustrated, the violation is registered consciously to the individual as a proposition, and the offending habit is identified. Humans can then regulate and change those habits by the conscious application of logic through deliberation. The applicable logic is Ramsey’s decision theory, which aims to make beliefs probabilistically coherent by adopting the laws and chances that signify the habits people might use for guiding behavior. The outcome of this deliberation is to refashion psychological expectations as mathematical expectations on laws and chances. These mathematical expectations are forecasts, and a forecasting theory of science takes scientific theories to provide forecasts.