I appreciate your question, but I think "we know" is problematic:
who is "we"?
how do we "know"?
can some people know one thing while others know the opposite?
I'm not trolling, either, just asking questions from a philosophical point of view. I've changed my mind about several things I took very seriously and thought I was 100% right about. Could others be dealing with similar changing-mind-through-time processes? Could you?