Chapter II. On Those Things which Constitute a Human Act

As is gathered from the very definition of a human act, three things concur to constitute it, namely knowledge, volition, and liberty. Since discussion concerning knowledge will occur throughout the whole Treatise on Conscience, here only volition and liberty will be spoken of under the single word voluntary; not because voluntary and free are the same, but because in the acts by which man as wayfarer tends to his end, in reality they are never separated, and thence they are used promiscuously by the moral theologian. First, then, some notion will here be given of the voluntary in general, and then of the voluntary in species, or rather of the indirect voluntary, for this species of the voluntary is very necessary to know and liable to difficulties.