The grounding objection asks the question: By what means or grounds does God know what he knows (particularly middle knowledge)?
Suppose I have an argument similar to the grounding argument from the grounding objection claiming that contingent truths are not self-explanatory but must simply exist, from all eternity, as an ungrounded, metaphysical surd. How would I, as a Molinist, respond?
This objection is merely the result of misunderstanding the means by which God knows what he does. God’s knowledge is wholly intuitive and relies on no existent entity and is completely compatible with divine aseity. According to Luis de Molina,
God does not get his knowledge from things, but knows all things in himself and from himself; therefore, the existence of things, whether in time or eternity, contributes nothing to God’s knowing with certainty what is going to be or not to be… For prior to any existence on the part of the objects, God has within himself the means whereby he knows all things fully and perfectly; and this is why the existence of created things contributes no perfection to the cognition he has of them and does not cause any change in that cognition… [And] God does not need the existence of those things in his eternity in order to know them with certainty.
 Luis de Molina, On Divine Foreknowledge, trans. Alfred J. Freddoso (Ithaca, NY: Cornell University Press, 1988), 4.49.12, 11.