The Six Books of Proclus on the Theology of Plato, Volume 2

For so far as it is cause, it is more perfect and more powerful than that which is posterior to it, and in consequence of this is the cause of a greater number of effects. For it is the province of a greater power to produce more, of an equal power to produce equal, and of a less power to produce a less number of effects. And the power which is able to effect greater things among similars, is also capable of effecting such as are less. But that which is able to effect such as are less, is not necessarily capable of producing such as are greater. If, therefore, the cause is more powerful, it is productive of more numerous effects.

Moreover, such effects as the thing caused is able to produce, the cause is in a greater degree able to produce. For every thing which is produced by secondary natures, is in a greater degree produced by such as are prior and more causal. The cause, therefore, gives subsistence together with the thing caused to such effects as the thing caused is naturally adapted to produce. But if likewise it produces prior to it, it is indeed evident that it energizes prior to the thing caused, according to the energy which is productive of it. Every cause, therefore, energizes prior to the thing caused, and together with it, and posterior to it, gives subsistence to other things.

Hence, it is evident, that of such things as soul is the cause, intellect also is the cause; but that soul is not also the cause of such things as intellect is the cause. But intellect energizes prior to soul. And such things as soul imparts to secondary natures, intellect also imparts in a greater degree. Likewise, when soul no longer energizes, intellect imparts by illumination the gifts of itself to those things to which soul does not impart herself. For that which is inanimate, so far as it participates of form, participates of intellect, and the production of intellect. Moreover, of such things as intellect is the cause, the good also is the cause; but not vice versa. For the privations of forms subsist from the good; since all things are from thence. But intellect being form, does not give subsistence to privation.