However, just because there is no proof does not mean unequivocally that the phenomenon does not exist. It means tht there as of yet has been no concrete proof. The idea that "no proof means non-existence" is equivalent to the "earth is flat" concept which was accepted as fact prior to 1492. All that it took was the proof. Copernicus and Galileo come to mind as well.
I don't have any issues with saying that you don't believe in something because you're never seen the proof. I think that most of us are like that on many issues. However, to just blatantly deny total existence of something and treat that nonexistence as fact because you don't have proof that fits your standards is misguided in my opinion.
John: Actually, all educated people in 1492 knew that the earth was round, and had known that for some time. Christopher Columbus wasn't the one that finally convinced everyone of that I should look to see at about what time it became generally accepted that the Earth is a sphere... in any case, it was well before 1492.
(I don't know what the uneducated people thought )