Ames: an implicit, virtual decree grounds conditionals that never occur; they belong to the knowledge of vision
William Ames explains the matter this way in his rescript to Grevinchoven's Response, chapter 15. 'This too,' he says, 'deserves careful consideration. A decree of God may be conceived either as a formal and explicit statute, or as implicit and virtual, contained by the force of another decree. Only the implicit kind applies to conditional contingent futures that never come to exist, because by the force of actual decrees they would exist if this or that were posited.
God had decreed to free David from the men of Keilah by means of flight, not by changing their minds outside the usual order. From this actual decree flows the conditional contingent: if David does not flee, he will be handed over.'
In this sense, Ames says, the conditional future rests on the free decree and so is understood by the knowledge of vision. That knowledge covers not only what will absolutely happen, but also what would flow from an actual decree already made, given this or that condition.
Latin
XLI. Sic rem istam exponit Guil. Amesius in sua rescriptione ad Grevinchovii Responsum cap. 15. Dignum, inquit, & hoc accurata contemplatione: decretum Dei vel ut formale statutum & explicitum concipi, vel ut implicitum & virtuale, quod virtute alterius decreti includitur: implicitum vero tantum dari in futuris conditionatis contingentibus, quae nunquam existunt, quia virtute actuali decretis, hoc vel illo posito existerent. Decreverat Deus liberare Davidem a manibus virorum Ceilae mediante fuga, non mutatione animorum praeter ordinem. Ex hoc actuali fluit conditionatum illud contingens: si non fugiat David, tradetur. Et hoc sensu ait futurum conditionatum decreto libero inniti, adeoque per Visionis scientiam intelligi, quae non sit de iis tantum quae absolute futura sunt; sed & de iis quae ex actuali decreto jam facto fluerent, hac vel illa conditione posita.