I don't have any proof, other than the circles themselves. U.F.O.'s created them? How in the hell should I know. I've read reports and seen photos; read about the anomolies ie: stalks bent and not broken - and much more detail on this issue but not the time lol.; personally witnessed a u.f.o. with my wife beside me (again, e.t. spaceship or not I can't prove but it sure didn't feel like a black project unless the american air force is secretly swiping Canadian salmon to feed the troups).
I have yet to see an adequate explanation for any of the anomolies. I could be very much behind the times though. If I am, I hope someone points out where to find the explanations.
Are proof and belief always remotely separate? I would argue that possessing a powerful enough belief in something often leads to proof. Isn't that what archeological finds of significance have often shown. Sure, some lucky strikes but mostly researching of old 'myths', believing in the clues that were discovered, and seeking out the same.