An example could be the gecentric model of the universe. A lot of groups belived this, then observation (evidence) that anybody with the knowhow could verify, for themselves, proved it incorrect. That is an example of evidence. It doesn't rely on subjectivity and can be verified by anybody. That is better evidence then a group of individuals agreeing on something and making the claim that their agreement is proof of the truth of that which they agreed on.
"I'm thick." - Me