So if the future really is unwritten, even for God, what does that mean for how we approach life? That's the kind of question that can take a lifetime to answer; it certainly has implications for every aspect of our theology. And aside from beginning to shed the general sense of fatalism that's colored my view of the world for as long as I can remember, it's a question I'm only just beginning to explore.
For some issues it has very direct implications; some of the biblical passages that Christian Universalism uses to build its case, for example, take on a very different meaning when filtered through the lens of Open Theism. Although universalists wouldn't necessarily have to abandon their position in order to adopt Open Theism, it would require them to reformulate a number of their arguments.
And the notion of praying for one's future spouse (before one has met that individual) only makes sense if one can assume that God already knows who that individual is; if the future is indeed unwritten, then such a prayer is an exercise in futility. Not that such a prayer was necessarily biblical in the first place, but it's nonetheless become a part of popular evangelical culture.
In terms of the Great Debate that I've examined on this blog over the last year, it doesn't appear to provide any significant advantage to either side. Those who are most inclined toward ex-gay philosophy are among the least likely to accept the idea of Open Theism, for reasons that have nothing to do with the issue of homosexuality; they're simply likely to come from those conservative camps that regard such a notion as heresy.
And yet Open Theism can arguably be used to support their position. If God already knows the future, then he knew from the beginning of time exactly who would turn out gay and which of those individuals would ultimately leave the church (or never gravitate toward it) as a result of the rejection they would face at the hands of his people. Within the traditional model, then, it's difficult to truly escape the implication that God is the author of same-sex attractions, since at the very least he did nothing to prevent that which he fully knew would take place. Of course, theologians have written entire libraries debating over statements like the one I just made, but ultimately it all comes out sounding like an endless exercise in semantics.
Meanwhile, Open Theism offers the genuine possibility that homosexuality is something that God honestly did not intend. It's not a slam dunk argument, as it still requires that one accept certain preconceived assumptions, but it does potentially dampen the wind in the sails of the "God made me gay" camp. One still has to address the fact that God would have seen the introduction of homosexuality into his creation as at least a strong possibility - I say 'strong' since its consistent presence in similar proportions in every known society throughout human history (not to mention the animal kingdom) argues that its potential (if not its inevitability) was present within the matrix of God's original design.
(Not that ex-gay advocates are necessarily averse to such a possibility; Elizabeth Moberly's theory on the origins of homosexuality, which is still popular in many ex-gay circles, states that same-sex attractions are the byproduct of a reparative process that's hard-wired into our psychological makeup. Of course, Moberly's theory also assumes that this reparative process can be tapped into to restore an individual to heterosexuality, a conclusion that the real world has yet to vindicate, so the ex-gay movement would probably be best served to move on in search of better theories.)
On the other side of the debate, if God does not know the future in advance, then it makes perfect sense that the Bible would stick to addressing situations that were actually being faced by the biblical authors. Many of the issues we face in contemporary society, though similar in some respects to those faced by previous generations, were mere possibilities in biblical times. Had God tried to address every possible future situation in the Bible (even just the likely ones), it would have had to be hundreds of thousands of pages long.
Thus one wouldn't expect the Bible to address the issue of same-sex marriage, since such an idea wouldn't have occurred to people (even those with homosexual orientations) living in an age when marriage and procreation were economic imperatives and romantic love was an incidental byproduct that followed after marriage, if at all.
The existence of individuals that are predominantly same-sex attracted wasn't completely unknown in biblical times, but that makes it all the more instructive that the Bible's condemnations of homosexual behavior were directed specifically toward its manifestations in idolatry and prostitution, just as it does under the traditional view of God and time.
The debate still comes back around to the question of whether homosexuality is directly contrary to God's character or merely an unintended variance from his original template (or something he intentionally and positively brought into being, but that argument is beyond the scope of what I want to address here). If the former, as most conservatives would advocate, then no homosexual relationship could ever be a good thing, regardless of any other considerations. Such a stance requires reading certain assumptions into the relevant biblical texts, however, so it ultimately becomes as much a matter of defending those assumptions as it is of debating over what the Bible actually says.
If the latter is true, however, then the idea of same-sex marriages is not necessarily beyond the bounds of those principles that we use to judge other relationships: self-sacrificial love, fidelity, tempering of character, trust, mutual respect, creativity, etc. It may not have been what God intended when he first created Adam and Eve, but we serve a God whose plans cannot be thwarted for long, a God who can use even the most seemingly useless person in incredible ways, a God who revels in making good come out of what appears to us to be the bleakest of situations.
The same God who used a bloodline that included liars, murderers, adulterers, prostitutes, Gentiles and idolators to rule over his chosen nation and to ultimately give birth to the Messiah is certainly great enough to make use of a group of people (homosexuals) that many of his followers regard as the lowest of the low. In fact, it's precisely the sort of thing that a student of the Bible ought to expect from such a God.
Whether gay marriage lies within the scope of God's will is a debate that won't be resolved anytime soon, but in any case it would be worthwhile for Christians on both sides to remember the heart that the God they worship has for "the least of these."