Morals do not exist in nature and thus cannot be discovered. In nature there are just actions - physical actions, biological actions, and human actions.
Human actors act to increase their happiness, however they personally define it.
Their actions become moral or immoral when someone else judges them as such. Thus, morality is a strictly human creation, subject to all the cultural influences and social constructions as other such human creations. A society that seeks greater happiness for its members by giving them greater freedom, will judge a Hitler or a Stalin as morally intolerable because his goal is the confiscation of human life, without which one can have no happiness. As long as it is understood that morality is a human construction influenced by human cultures, one can become more tolerant of other human belief systems, and thus other humans. But as soon as a group sets itself up to be the final moral arbiter of other people's actions, especially when its members believe they have discovered absolute standards of right and wrong, it is the beginning of the end of tolerance and thus, reason and rationality.