P6: The force of any passion, or affect, can surpass the other actions, or power, of a man, so that the affect stubbornly clings to the man.

Dem.: The force and growth of any passion, and its perseverance in existing, are defined by the power of an external cause compared with our own (by P5). And so (by P3) it can surpass the power of a man, etc., q.e.d.