But the Jesuits, entering the discussion, brought change.
...Though in fact opposed by the Thomists and Augustinians (e.g., by Bannez, the Salmanticenses [Carmelites of Salamanca, Spain], and Billuart), this theory of middle knowledge was also hotly defended by Molinists and Congruists (Suarez, Bellarmine, Lessius, et al.). Fear of Calvinism and Jansenism favored the theory in the Catholic church and in a more or less pronounced form gained acceptance with almost all Roman Catholic theologians.
...Now with respect to this middle knowledge the question is not whether things [or events] are not frequently related to each other by some such conditional connection, one that is known and willed by God himself. If this is all it meant, it could be accepted without any difficulty, just as Gomarus and Waldeus understood and recognized it in this sense. But the theory of middle knowledge is aimed at something different: its purpose is to harmonize the Pelagian notion of the freedom of the will with God's omniscience. In that view, the human will is by its nature indifferent. It can do one thing as well as another. It is determined neither by its own nature nor by the various circumstances in which is has been placed. Although circumstances may influence the will, ultimately the will remains free and chooses as it wills. Of course, freedom of the will thus conceived cannot be harmonized with a decree of God; it essentially consists in independence from the decree of God. So far from determining that will, God left it free; he could not determine that will without destroying it. Over against that will of his rational creatures God has to adopt a posture of watchful waiting. He watches to see what they are going to do. He, however, is omniscient. Hence, he knows all the possibilities, all contingencies, and also foreknows all actual future events. In this context and in keeping with it, God has made all his decisions and decrees. If a person in certain circumstances will accept God's grace, he has chosen that person to eternal life; if that person does not believe, he or she has been rejected.
Now it is clear that this theory diverges in principle from the teaching of Augustine and Thomas Aquinas. Certainly, to their minds God's foreknowledge precedes events, and nothing can happen except by the will of God. "Nothing, therefore, happens but by the will of the Omnipotent." [Enchiridion] Not the world but the decrees are the medium from which God knows all things. Hence, contingent events and free actions can be infallibly known in their context and order. Scholasticism, admittedly, sometimes already expressed itself on this point in a way that was different from Augustine. Anselm, for example, stated that foreknowledge did not imply an "internal and antecedent necessity" but only an "external and consequent necessity." And Thomas judged that God indeed knows contingent future events eternally and certainly according to the state in which they are actually, that is, according to their own immediacy, but that in their "proximate causes" they are nevertheless contingent and undetermined. This, however, does not alter the fact that with a view to their "primary cause" these contingent future events are absolutely certain and can therefore not be called contingent. And elsewhere he again states that "whatever is was destined to be before it came into being, because it existed in its own cause in order that it might come into being."I'd say that was pretty good, eh?
The doctrine of middle knowledge, however, represents contingent future events as contingent and free also in relation to God. This is with reference not only to God's predestination but also his foreknowledge, for just as in Origen, things do not happen because God knows them, but God foreknows them because they are going to happen. Hence, the sequence is not necessary knowledge, the knowledge of vision, the decree to create (etc.); instead, it is necessary knowledge, middle knowledge, decree to create (etc.), and the knowledge of vision. God does not derive his knowledge of the free actions of human beings from his own being, his own decrees, but from the will of creatures. God, accordingly, becomes dependent on the world, derives knowledge from the world that he did not have and could not obtain from himself, and hence, in his knowledge, ceases to be one, simple, and independent - that is, God. Conversely, the creature in large part becomes independent vis-a-vis God. It did indeed at one time receive "being" (esse) and "being able" (posse) from God but now it has the "volition" (velle) completely in its own hand. It sovereignly makes it own decisions and either accomplishes something or does not accomplish something apart from any preceding divine decree. Something can therefore come into being quite apart from God's will. The creature is now creator, autonomous, sovereign; the entire history of the world is taken out of God's controlling hands and placed into human hands. First, humans decide; then God responds with a plan that corresponds to that decision. Now if such a decision occurred once - as in the case of Adam - we might be able to conceive it. But such decisions of greater or less importance occur thousands of times in every human life. What are we to think, then, of a God who forever awaits all those decisions and keeps in readiness a store of all possible plans for all possibilities? What then remains of even a sketch of the world plan when left to humans to flesh out? And of what value is a government whose chief executive is the slave of his own subordinates?
In the theory of middle knowledge, that is precisely the case with God. God looks on, while humans decide. It is not God who makes distinctions among people, but people distinguish themselves. Grace is dispensed, according to merit; predestination depends on good works. The ideas that Scripture everywhere opposes and Augustine rejected in his polemic against Pelagius are made standard Roman Catholic doctrine by the teaching of the Jesuits. (Herman Bavinck, Reformed Dogmatics, vol II, p. 199-201)