ABSTRACT
Logic textbooks as a rule talk about two kinds of implication, strict implication (entailment) and material implication. But epistemic implication is neither. If epistemic implication holds good, then an 'ought' is only supported if certain facts obtain and not others. Epistemic implication which constitutes the logic of justification in the domain of ordinary knowledge must not be confused with what is called epistemic logic. Epistemic implication and doxastic logic differ in two ways: in their ontological and semantical implications. The demand of epistemic implication is no more than the demand that one is interested in establishing good arguments and not bad ones. The notion of epistemic implication tries to explicate what is meant by 'evidence may be critically assessed'. The prescriptive use of language presupposes the descriptive use of language. This insight is indeed not lost on the positivist moral philosophers.
