Following along from http://www.askphilosophers.org/question/2039:
"Does the law of bivalence demand that a proposition IS either true or false today? What if the truth or falsity of this proposition is a correspondence to a future event that has yet to occur?"
What's problematical about saying "yes, it's either true or false, but I don't happen to know which"? Is that substantively different from saying the same thing about an open problem in science or mathematics, to which the answer is presumably knowable but happens not yet to be known? The questioner seems to be demanding both that there be an answer, which may be a reasonable thing to want, and to be able to know what the answer is, which isn't necessarily reasonable. Is it reasonable always to expect somebody (other than deity) to know the answer to a question?