Article one reports the historical De Auxiliis dispute between Jesuit Molinists and Dominican critics, a controversy Rome eventually declined to settle. The objection that keeps Molinism contested among philosophers today is different from, and sharper than, the one the Dominicans originally pressed, and it is worth stating on its own terms.
Robert Adams's 1977 paper on middle knowledge raised what is now generally called the grounding objection. Molinism requires that there be, prior to God's decision to create anything, definite truths about what any possible free creature would freely choose in any circumstance, the "counterfactuals of freedom" that supply God's middle knowledge. Adams's challenge is to ask what makes such a counterfactual true before the creature exists and before the choice is ever made. An ordinary truth is grounded in something, a fact about the world, a law, an actual event, but a counterfactual about a genuinely undetermined choice seems to have nothing available to ground it: not the creature's actual choice, since it never occurs in that circumstance, and not the creature's nature, since a free choice is defined as not settled by prior facts about the chooser.
Molinists have replied in more than one way, some denying that such counterfactuals need external grounding at all, others proposing they are brute truths built into the space of possible worlds from the start. Neither response has persuaded critics generally, and the debate remains substantially where Adams left it: a live and unresolved technical dispute, distinct from the older theological worry about grace and merit that drove the original sixteenth-century argument article one describes.