My mother likes to wear a T-shirt which says, "Scientists should clearly state the theories on which their facts are based." Darwin's theories of evolution fit in quite nicely with England's economic theories of the time. No science can be completely objective, although it is a laudable goal. The best you can do is declare all known biases and let the reader beware. The harm that some scientists and an eager public do is let science claim absolute truth in whatever they are doing instead of publishing reasonable doubt. In many cases the burden of proof falls too heavily onto one side, ie, prove that cigarettes are harmful not prove that they aren't. So I always like to check sources before making claims and I like to remember those sources when I'm repeating things. I also tend towards the simplest explanation probably being the closest to truth, but not always. Somebody once explained to me the ancient Celtic background behind the song The Two Sisters, The miller represented this, the sisters were these two.. etc. I thought it interesting but given that many of the variations of Two Sisters were made by people with no knowledge whatsoever of the mythology he was talking of, and that murder between people who are not gods has and does occur, I didn't think highly of the theory.