Abstract

Analyzing the process of keeping promise we identify its sequence structure and its phase sequences in time. This allows us to arrive at a time order principle forming according to which obligation performance cannot precede in time its sufficient or necessary conditions performance. We further observe that a given promise must always be taken as an element of a certain system of promises. As a result we review definitions of the terms sufficient condition and necessary condition as no more allowing their mutual defining, or symmetry . We try to discover the compliance rules concerning the condition – the conditioned vector, the course of events vector and the time vector. We conclude that it indicates an incorrect use if, provided the condition – the conditioned vector complies with the course of events vector, the negative time difference in the descriptive use of sentences involving either the if-then connective or the only if connective is obtained. Only when using sentences for abductive explanation with a dominating epistemic vector the negative difference of time does not indicate erroneous use; however, this is possible only for the term of sufficient condition. We further suggest reviewed definition generalization involving the terms of sufficient condition and necessary condition containing always a parameter element denot-ing a given modality type, or a particular system of rules, laws, etc. Such definition satisfies Brennan’s requirement of a “general formal scheme” where the notion of sufficient condition and necessary condition symmetry does not apply