  One might ask whether God possesses this same freedom in bestowing esse essentiae on possible essences, that is, on (doubly) secondary objects of His knowledge. Unlike what happens for the being of existence, the reply would seem to be negative in this case. As mentioned above, there is an asymmetry between the relation of efficient causality and the relation of formal dependence that conjoin creatures and Creator: while the former is in time, the latter is eternal. This means that the distinction between what is possible and what is not possible is necessarily such from eternity. Moreover, since essences can never cease to be in their essential being (that is, in their being eternally thought by God), they are absolutely necessary. As such, not only can they not be destroyed, but they cannot even be modified. In actual existence, all essences are equally indifferent with regard to the Creator's power, so that God can place in act one res before another as He chooses, without any mediation, whereas in their own being essences are arranged in a hierarchical order that God himself, on whom that order depends, cannot modify.