Objections: Scientia Media?
Since the early Church, theologians have suggested that there are two logical moments of God’s omniscience. This doctrine guards God’s knowledge from being dependent on creation and guard’s against the idea that creation involves merely actualized pre-existing ideas—the idea that all possible creations exist co-eternally with God as ideas that await not creation but actualization. The first logical moment of God’s thought is His natural knowledge (or simple knowledge); God’s natural knowledge contains all necessary truths and all knowledge about Himself. If a truth is eternally true and necessary in and of itself, it is found in God’s natural knowledge. This includes such things as abstract ideas; eg. The law of non-contradiction, numbers (the idea not the symbol representing it). Examples of necessary truths are; God exists, God is good, God is one and three. These are necessary because there is no way they could not be true; it is logically impossible for God not to be good, for then He would not be God. God’s natural knowledge also encompasses all possibilities.
The next logical moment of God’s omniscience is His free knowledge (or knowledge of vision). God’s free knowledge is His knowledge of all that arises from His decrees. “Ideas, considered antecedent to the decree of the divine will, represent an abstraction and only a possible existence. Considered after the determination of the divine will, they represent things which are to come in their actual existence.” This knowledge is considered “free” because it results from God’s free decisions. This division ensures that God’s knowledge is based on either His self-sufficiency (natural knowledge) or His decrees (free knowledge); it is not at all dependent on His creation. God from this understanding knows all future events; even before He created, He knew would and could happen, but this knowledge is not based on free human choices, it precedes them.
This effectively determines all human choices, leaving no room for free human choices. To answer the obvious compatibilist implications of this understanding of God’s omniscience, a Jesuit priest named Luis de Molina suggested a third moment in God’s knowledge between His natural and free knowledge; because of its place between the first and third moment of God’s knowledge, he called it scientia media, or middle knowledge. Molina’s middle knowledge described God’s knowledge of all that free creatures would do in every circumstance. It is knowledge that is dependent on God’s creatures, neither on God Himself nor on His decrees. This knowledge is supposed to contain all contingent truths (such as what a specific person would do in a specific circumstance).
Middle knowledge is a key piece in the FWD because it lays out every possible world that He could create. God knows through His middle knowledge what every creature He could create would do in every circumstance in which He placed him or her. In the FWD, it is suggested that it is possible that at least one person is transworldly depraved, meaning that in every possible world God could actualize this person would sin. In the FWD, God deliberates possible worlds to actualize via his middle knowledge. For this argument to work, God requires middle knowledge because He needs to know what His free creatures would do in every circumstance and see that they would fall. In the FWD, God then creates despite having this knowledge because a world of significantly free creatures was worth the cost of evil. Without middle knowledge, God’s knowledge would be determinative and it is no longer possible to say that God was unable to create a world without sin (premise 2); God would have been able to create a world without sin because His knowledge and creation was not constrained by dependence on the free choices of His creatures. To evaluate whether middle knowledge is actually tenable, we will now turn our attention to various objections raised against it.
Objection 1: Middle Knowledge Provides No Ground For How Can Know Future Contingent Choices.
The first, and most frequent, objection to middle knowledge is that it gives no way that God could know future contingent choices; it just assumes that this is possible. Can we even assume that a contingent choice can be true or false before it happens, what makes it true or false other than the choice being made? If a person is never in a circumstance to make a choice, how can we say that it is true or false that they would make it? Whatever it is that gives a ground for true propositions in God’s middle knowledge, it must be non-necessitating, for middle knowledge is by definition God’s knowledge of contingently free choices—to suggest a necessitating ground defeats the purpose of middle knowledge.
Someone may suggest that the intentions of those involved in a contingent choice provide a ground, but this brings up its own problems. These intentions have to be necessitating, making the proposition true and eliminating middle knowledge, or the proposition is neither true or false, only probable (if their intentions are non-necessitating then they could act contrary to them).
Molina suggested that God’s certainty of contingent choices came from what he called “supercomprehension.” He held “”that the certainty of that middle knowledge comes from the depth and unlimited perfection of the divine intellect, by which [God] knows certainly what is in itself uncertain.” This concept must be rejected in that it itself is a non-answer, it does not explain how God can know the uncertain, and it is incoherent. To comprehend something is to know everything there is to know about it, how could God know more than all there is to know?
Another Jesuit theologian, Francisco Suarez, suggested that there was a property in a free being that grounded God’s middle knowledge. Consider creature C, who may never exist, who would do possible action A in the possible circumstance S. God knows that C would do A in S because of a specific property of C, what Suarez called a habitudo. There are two problems with this explanation. First, this property would be in God’s idea of C and not in C himself, for God knew what C would do before he existed. This roots C’s action in God and not in C himself. Even if this could be avoided, the fact that there is something in C that renders certain what he will do in S shows that this property is a sufficient condition for A; if there is a sufficient condition for A, then it won’t work for middle knowledge. Probably the greatest reason to reject Suarez’s suggestion is that there is no reason to believe that this property exists.
One last suggestion that has been given for grounding God’s middle knowledge is the idea of backtracking counterfactuals. It is suggested that a person’s free choice is what has led to God’s knowledge of it. The first objection to be made would be to decry this as backwards causation, but Craig is careful to guard against this accusation. Craig suggests that there is merely a semantic relationship and not a causal one at play. A proposition is true because it corresponds to a true state of affairs. The correspondence of the proposition to reality is not causal but semantic. Take two time stamped propositions, (6) C will do A at S and (7) C did A at S. (6) is true before S but not after it, (7) is true after S. The proposition (8) C does A at S, is true at all times. What makes these propositions true is their semantic relationship to the actual state of affairs, it is not a causal relationship. There is no backward causation and since God knows all true propositions, He will know what C will do at S.
Because middle knowledge relies on Incompatibilist freedom, the backtracker explanation must be able to affirm that C is able to not do A at S—this is the “can-claim.” It is objected that the truth of this backtracker calls into question the can-claim. God had to have known the truth of the backtracker from all eternity, this means that a necessary condition of C doing something different than A at S is that the past be different. “Since the past is fixed and out of [C’s] control, it at least seems to follow from this that [C] can’t do [other than A].”
Though there is a difference between the counterfactual backtracker and a backtracking causal chain, there appears to be no difference in the fixity of their results, this difference must be proven for counterfactual backtrackers to ground God’s middle knowledge. Backtracking counterfactuals also appear to be begging the question, for it assumes that there is correspondence between an actual state of affairs and the proposition making it true, for if the actual state of affairs does not obtain, then there is no correspondence between the state of affairs and the proposition. How can this explain God’s middle knowledge of states of affairs that will never exist? Until C does A, how can God know that He will not do not-A? It appears then that there is no reason to attribute to man this strange ability of determining God’s thoughts in the past with our present actions, and that there is no reasonable answer to the grounding objection.
Objection 2: Middle Knowledge is Incompatible with Libertarian Freedom.
The next objection is that middle knowledge appears to be self-defeating; it requires libertarian free will yet it appears to render our choices necessary. For example, if C is to be free he must be able to choose either A or not-A at S. 100 years ago, God knew that at S, C would do A. Unless God’s knowledge is capable of error, C must do A at S. Without a non-necessitating ground for God’s foreknowledge, the proponent of middle knowledge is left with only compatibilist causality as the way for God to know with infallible certainty what C will do at S and no way to explain away objection 2.
Objection 3: Middle Knowledge Makes God’s Knowledge Dependent on Creation.
The third objection to middle knowledge is one we have already mentioned. If God’s middle knowledge is of the contingent choices of His free creatures, His knowledge is dependent on them. God’s omnipotence is then dependent on His creatures, at least part of it. We must ask, is it consistent with the Biblical picture of God for His knowledge to be dependent on created beings?
Objection 4: God Can Be Disappointed By the Future
Our last objection showed that middle knowledge calls into question God’s independence, this next objection calls into question middle knowledge’s ability to uphold God’s sovereignty. Unlike Open Theism, if God has middle knowledge, he will not be surprised by the future, but there is the possibility that He will be disappointed. As was made evident in the FWD, middle knowledge may result in God being disappointed. As Laing has pointed out,
it can hardly be said that middle knowledge allows God to “plan” the world he wants in the sense that he can insure that the most desirable “ends and purposes” of which he can conceive will always be achieved. Rather, it is possible for a God with middle knowledge to find himself disappointed in the sense that he may often have to settle for much less than the ideal.
The evangelical proponent of the FWD must ask himself or herself, “does this really fit the picture of the God of the Bible?” Does this really fit with the God who “works all things after the counsel of His will,” who is said to cause “all things to work together for good to those who love God”? Does this sound like the God who, in contrast with the idols of Babylon, declared Himself to be the one true God, “Declaring the end from the beginning,And from ancient times things which have not been done,Saying, ‘My purpose will be established,And I will accomplish all My good pleasure’” (Isa. 46:10).
Objection 5: Their Scripture Evidence Does Not Prove It.
Our last objection calls into question the biblical warrant for middle knowledge. Proponents of middle knowledge have argued that 1 Sam. 23:12 proves that God has middle knowledge. In this verse, David asks God if the men of the city Keilah would hand him over to Saul if Saul came down to the city, God responds, “They will surrender you.” It is argued that God would only have known this through His middle knowledge. The problem with this proof is that middle knowledge is not the only explanation, nor is it the most convincing.
All this verse shows is that God possess counterfactual knowledge, which can more easily be explained by God knowing the intentions and desires of those involved and how exactly they would respond in the circumstance if it arose.
Ames, The Marrow of Theology, 96. Cf. John A. Mourant, “Scientia Media And Molinism,” The Encyclopedia of Philosophy (New York, New York: Macmillan Publishing Co., Inc. & The Free Press, 1972), 338.
 Proponents speak of actualizing instead of creating because God is not creating undefined things but bringing into reality a specific set of contingent circumstances; there are eternally existing states of affairs, and God actualizes these by creating something, such as the heavens and earth. Plantinga, “Christian Apologetics,” 427.
William Lane Craig, “Divine Foreknowledge and Newcomb’s Paradox | Reasonable Faith,” ReasonableFaith.org, accessed April 17, 2014, http://www.reasonablefaith.org/divine-foreknowledge-and-newcombs-paradox.
 This assumes compatibilism, but in light of the evidence against middle knowledge and incompatibilism, it would seem reasonable to accept a compatibilist understanding of freedom. Campbell, Middle Knowledge: A Reformed Critique, 22.