 The difficulties facing the notion of eternal powers stem from the idea that there are unexercised but nonetheless genuine eternal powers, as Grosseteste’s account of non-temporal contingency seems to require.  Put in terms of God’s powers to know or will, one problem is what it could mean to say that God could have not known or willed what he in fact knows or wills (or the converse), as is implied, Grosseteste thinks, by the doctrine that God has the power to not know or not will what he knows or wills.  For “could have” expresses the priority of power to act, the idea that prior to God’s willing that p, he had a power not to will that p. But God is not in time and thus “could have” cannot express a temporal priority of God’s power to its act.  Grosseteste’s solution to this problem is to hold that it expresses a so-called causal priority, a notion he drew from Eriugena (Grosseteste prefers not to call it a natural priority since there is no distinction of natures involved in God’s power and act) (see Lewis 1996).