Jansenius: reason and will reflect on their own acts, so the rational agent always moves itself
To show more plainly that a rational agent in some way acts and moves itself in everything it wills and desires, even when its act of will is necessary and unchangeable, he observes where the power of self-action and self-movement lies, the power that belongs to a free agent.
It lies in the fact that both reason and will, the faculties to which freedom belongs, can turn back on their own acts. Reason can judge its own judgment and ask whether it judged rightly. The will likewise can not only will and desire but also will its own willing and its own desire.
In every rational motion, necessary or not, such reflection on itself is always present, silently or openly. So in every motion a rational agent always moves itself and is master of itself, and in this way exercises its own freedom.
Latin
XXXII. Atque ut clarius ostendat agens rationale in omnibus quae vult & appetit, seipsum quodammodo agere & movere, etsi actus voluntatis ejus necessarius sit & immutabilis, observat potestatem agendi & movendi se, quae est agentis liberi propria, in eo sitam esse, quod tum ratio, tum voluntas, ad quas facultates libertas pertinet, super suos actus se reflectere possint; ita ut ratio possit de proprio suo judicio judicare, num recte judicaverit; & similiter voluntas non solum possit velle & appetere, sed ipsam quoque suam volitionem, suumque appetitum velle. Et quia in omni rationali motu, sive necessarius sit, sive non necessarius, semper adest tacite, vel expresse, hujusmodi super se reflexio, semper etiam in omni suo motu agens rationale seipsum movet & dominatur sibi, & ita propriam libertatem exercet.