P14: No affect can be restrained by the true knowledge of good and evil insofar as it is true, but only insofar as it is considered as an affect.

Dem.: An affect is an idea by which the Mind affirms of its Body a greater or lesser force of existing than before (by the general Definition of the Affects). So (by P1), it has nothing positive which could be removed by the presence of the true. Consequently the true knowledge of good and evil, insofar as it is true, cannot restrain any affect.

But insofar as it is an affect (see P8), it can restrain the affect, if it is stronger than it (by P7), q.e.d.