All we have are opinions.
Most of the stuff that different religions and denominations argue over is just that, an opinion, an opinion made by one man 1700 ( Augustin Hippo) years ago or even one made less than 100 years ago ( Rutherford), but still just an opinion.
Are all opinions equally valid? For example, do the opposing opinions of Richard Friedman and the Watchtower Society with regards to the validity of the Documentary Hypothesis hold equal weight?