It follows that. Folgerung. That doesn't follow. Non sequitur. Wherever we look, logical consistency or inconsistency is expressed metaphorically in terms of time. So elementally do we link “after” and “because” that the most common fallacy, by which historians make a living, is post hoc ergo propter hoc: “thereafter, hence because of it.” Conversely, we should say that propter hoc ergo post hoc must inevitably be valid: “because of it, hence thereafter.” There is, however, one respect in which this need not be held to be true—the teleological. Causa finalis, the ultimate purpose, lies inevitably in the future, as indeed does every purpose. Tomorrow's concert causes today's rehearsal. True, your reason for rehearsing necessarily precedes your rehearsal, but the cause of your reason may be said to lie in the future inasmuch as the future is foreseeable. In this sense, then, propter hoc ergo post hoc can be fallacious too. Tomorrow you have a concert. It doesn't follow that you want a rehearsal today; it precedes.