Science is based upon the null hypothesis. Nothing is science is based upon 100% certainty, but upon degrees of probability. It is very common for scientists to conveniently forget this point and try and frame their understandings as being "fact".
Major advances in science have taken place because scientists formulate alternative understandings of events. Low and behold, when they develop means and methods for determining that this "new" understanding has a high probability of explaining things, other people change their minds and accept the new "facts."
Strident assertions of understandings should be balanced by keeping an open mind to alternative explanations. I like to say that I am the first to put my ideas out there and the first to admit that they are wrong when presented with information that leads me to rethink my current position.
I am always open to new ideas; I just have never heard a really good reason to believe in ki
. So until I hear one, I'm going to go on being an unbeliever.