It's logical fallacy time!
"My theory may sound pretty crazy now, but soon everyone will come around. The scientists will find evidence validating my theory, and then there will be the biggest scientific revolution since Einstein! If you buy my book, you can be at the front of that revolution, and tell your grandchildren all about it."
This should be an obvious one. Evidence is useless unless it is present. As in, the evidence exists right now, at this moment. Evidence from the future doesn't mean a thing. 'Cause if the evidence doesn't exist yet, how do you know that it will ever exist? What evidence do you have to support such a prediction?
Future evidence is never a certain thing. Evidence is essentially a piece of information or an observation which makes a claim more likely than we previously thought. If we knew for sure that we were going to find evidence in the future, than this piece of knowledge counts as present evidence.
Science is not about going out and finding evidence for your ideas. It is about determining whether there is evidence for your ideas, or evidence against them.
Anyways, there is no shame in being wrong when the current evidence is incomplete, thus pointing you in the wrong direction. If, for instance, you believed in evolution prior to the 19th century, you would be correct in the sense that evolution was correct. But you would be incorrect in that you believed a scientific claim without any evidence to support it. If you believe lots of things which are unsupported by current scientific evidence, you might occasionally be correct. But far more often you'll be incorrect, because you've basically abandoned the scientific method in favor of the guessing method.