An unknown hypothetical cannot justify anything. And so when someone says, “Perhaps in the future, some other worldview besides Christianity will allow for the possibility of knowledge,” one possible reply would be: “Then in the future, that worldview could be considered rational. But right now, only Christianity can justify knowledge.” Of course, no such worldview will be discovered in the future. But my point is that appealing to the unknown can never justify a positive belief. It’s irrational to say, “I have a great reason to believe in space-aliens, and that reason is this: someday in the future, somebody might find some evidence of them.” Present (true) beliefs must be justified by present reasons if they are to be considered knowledge.