They like the open theists denied the exhaustive foreknowledge of God, and redefined omniscience to accommodate their commitment to libertarian free will.
Socinians. Now there's an unfamiliar word in today's evangelical world. It is so obscure you instinctively think it must be irrelevant, so old that you want to blow the dust off it, and that some weirdo doing a Phd is about the only person interested in it (in case you were wondering, that's not me).
Even in the late nineteenth century Thomas Carlyle referred to the "dusthole of extinct Socinianism." But not all of their ideas were extinct. It would be better to say that they lay dormant.
It was somewhat curious, in the mid 1990s, that the openness proposal should have been feted as a new insight free from the shackles of philosophy and more in tune with Scripture. The truth is that it was old, had been tried and found wanting, and was well understood to be beholden to a particular, philosophical, view of the will, a view rejected as incoherent and unscriptural. Read Luther and Edwards on the freedom of the will and see for yourself.
The denial of God's exhaustive foreknowledge was well past its "sell by" date long before evangelicals gave it air time, column inches, the imprimatur of their big publishing houses, and public platforms.
Our best theologians and historians, from previous generations, had described, engaged with, and discarded the denial of God's exhaustive foreknowledge. See the references in earlier posts from Martin Luther (1483-1546), John Owen (1616-1683), Jonathan Edwards (1703-1758), William Cunningham (1805-1861), Charles Hodge (1797-1878), A. A. Hodge (1823-1886), and Herman Bavinck (1854-1921).
Compare the following words from Pinnock with those from Gresham Machen (first published in 1937):
However, omniscience need not mean exhaustive foreknowledge of all future events. If that were its meaning, the future would be fixed and determined, much as is the past.Machen wrote:
Total knowledge of the future would imply a fixity of events. Nothing in the future would need to be decided. It also would imply that human freedom is an illusion, that we make no difference and are not responsible. (The Openness of God, p. 121)
Is not man's freedom of choice a delusion if all is fixed in God's eternal plan?
There are those who have been impressed by this objection and have actually regarded the personal choices of persons, especially man, as lying outside the range of the things fixed in God's eternal purpose.
When God created persons, they have said, He left the persons free; otherwise they would not have been persons at all.
This view may be held in two forms. In the first place, those who hold it may say that God does not even know beforehand what choices the persons whom He has created will make...
The former of these two forms of the theory seems to do away with the omniscience of God.
If God does not know what His creatures, including man, will do, then a wild, unaccountable factor is introduced into the universe. Can that unaccountable factor be isolated? Can we hold that although God does not know what the persons whom he has created will do, yet He can go on governing the rest of the universe in an orderly fashion?
If God does not know what the personal beings in the universe will do, then the whole course of the world is thrown into confusion. God, moreover, on that view, ceases to be God.
He becomes a being who has to wait to see what His creatures will do; He becomes a God who has to change His plans to meet changing circumstances. (The Christian View of Man, p. 38-9)