Open Theism is the view that God chose to create a world that included free agents, and thus a world where possibilities are real. The future is pre-settled, to whatever degree God wants to pre-settle it and to whatever degree the inevitable consequences of the choices of created agents have pre-settled it. But the future is also open to whatever degree agents are free to resolve possibilities into actualities by their own choices.
In the open view, God knows everything perfectly, including the future. But since the future is partly comprised of possibilities, God knows it as partly comprised of possibilities.
This doesn’t in any way take away God’s sovereignty, for in the open view, God has unlimited intelligence. While beings with limited intelligence are more prepared for certainties than possibilities (because the more possibilities they have to anticipate, the thinner they have to spread their intelligence), the infinitely intelligent God is just as prepared for each and every future possibility as he is a certainty. Whatever comes to pass, God has been anticipating that very event from the foundation of the world as though it had to occur. It’s just that in the open view, God is so smart, it didn’t.
People sometimes worry that if the future isn’t foreknown as exhaustively settled, God can’t promise to bring good out of evil or defeat evil altogether in the end. Without knowing it, however, people who worry in this way are insulting God’s intelligence. If we trust that God’s intelligence is unlimited, we can remain confident that whatever comes to pass, however evil, God has been from the foundation of the world setting up a plan to respond to it. And we can affirm this without having to suggest that evil was originally part of his plan.
The open view has many positive implications for believers. It allows us to affirm that evil is not in any sense part of God’s plan for our lives, even though he perfectly anticipates it and can promise to redeem good out of it. It also means that our lives really make a difference. In the open view people have genuine “say-so” in what comes to pass. Things really depend on what humans do, including whether or not people pray.
For more on this, see G. Boyd, God of the Possible (Baker, 2000).