Open Theism (Also known as Free Will Theism or Openess Theology) is the belief that God does not know the future. Most versions of this teach that the future is not settled, and therefore God does not know what will happen. This heresy essentially denies God's omniscience.
This heresy is often considered a form of Limited Theism, which denies God's omnipotence, because Open Theism denies God's ability and power to know the future. Many adherents to Open Theism are Pelagians. Muggletonianism will sometimes lead to Open Theism.
Why is it Heresy?
Open Theism is heresy because it denies the Omniscience of God. In doing so, it sets up an idol and follows a false god rather than the God of the Bible.
Etymology
Open Theism is named because most proponents teach that the future isn't settled, therefore it is "open". Theism is the belief in a
History
A form of Open Theism was taught by Faustus Socinus in the 1500s. In the Mid-To-Late 1600s, Lodowicke Muggleton, founder of Muggletonianism, taught that God did not know what was happening on Earth and therefore did not intervene in everday events.
Open Theism was first taught as an organized doctrine in 1980, when Richard Rice released his book entitled The Openness of God. In 1994, Rice collaborated with other authors to write five different essays further expounding on this heresy. After this, it gained a lot of traction.
In more recent years, this heresy has been promoted by Greg Boyd, Clark Pinnock, C. Peter Wagner, Dallas Willard, and Shawn Bolz. Many of those within the Pelagian resurgence, including Jesse Morrell and Jed Smock, are also Open Theists.