The principle of total evidence reprised

The Principle of Total Evidence, postulated by Carnap in 1947, implies that to achieve the best assignation of a probability, all available information should be considered, subject to cost. For the evaluation of evidence, it is important that the best assignation of probability be made. The benefits of such an assignation are shown to be an increase in the expected utility of any decision made, a decrease in an expectation of an error of an inference that might be made and an increase in the expected weight of evidence for the correct hypothesis. A practical illustration is given with reference to a recent Italian case.