Subjectively Certain Inference

Abstract

When all the certainty is transferred from the premisses to the conclusion, for instance, when on the strength of accepting the premisses with full certainty we arrive at the acceptance of the conclusion with full certainty, then such a procedure is valid only if the truth of the premisses guarantees the truth of the conclusion, i.e., if the conclusion follows from the premisses. But in evaluating the conclusiveness of subjectively certain inference we do not rest satisfied with the requirement that the conclusion should just follow from the premisses, but we require the conclusion to follow from the premisses logically. Subjectively certain inference in which the conclusion follows logically from the premisses is evaluated as formally correct, whereas inference in which the conclusion does not follow logically from the premisses is said to suffer from a formal error.