Hence the voluntary is a genus with two species, and the spontaneous a wider genus still
They therefore deny that what is voluntary is free when the will is necessarily fixed on it, as the will of the blessed spirits is fixed on loving the God they see clearly.
So they treat the voluntary as a genus with two species under it. One is the free, which is done with selection and preference. The other is the voluntary in the strict and proper sense, which is done gladly but not freely, because it is done necessarily and unchangeably.
Above the voluntary they place the spontaneous as its genus. For not only beings with intellect and will act of their own accord, but also brute animals without reason, and even lifeless things, such as a stone moving downward, since acting spontaneously means acting on nature's impulse.
Latin
XXXIX. Itaque quod voluntarium est liberum esse nolunt, si voluntas sit ad illud necessario determinata, ut Beatorum Spirituum voluntas ad diligendum Deum quem clare vident. Ac proinde voluntarium concipiunt tanquam genus quoddam, quod sub se duas species complectatur, videlicet liberum quod fit cum delectu & praelectione, & voluntarium stricte & proprie sic dictum, quod fit quidem libenter, non tamen libere; quia necessario & immutabiliter. Voluntarii vero genus faciunt spontaneum, quoniam sponte agunt non tantum ea quae sunt intellectu & voluntate praedita, sed etiam bruta quae ratione carent. Imo & ipsa inanima, ut lapis quum deorsum tendit. Nam sponte agere est naturae impulsu agere.