Everything that comes out of our mouths is, ultimately, just our opinion.  "Facts" can be proven and disproven based on personal experiences, studies, etc.  Greater technology helps us learn what is really happening within the body, yet so much is still a mystery.  And one body is so uniquely different than another.  Bottom line, when others start citing "facts", just remember that no one knows everything, and to take it as their opinion, whether it is based on personal experience or information.  '