The moral dilemma called The Trolley Problem has been mulled over for decades by philosophers and linguists. It was first created by Philippa Foot, a moral philosopher living in England. The problem as slightly re-formulated by Judith Jarvis Thomson is:
A trolley is hurtling down a track towards five people. You are on a bridge under which it will pass, and you can stop it by dropping a heavy weight in front of it. As it happens, there is a very fat man next to you – your only way to stop the trolley is to push him over the bridge and onto the track, killing him to save five. Should you proceed?
These are artificial thought problems, but morality cannot be considered outside reality and thus depends greatly upon the complex situation. Tens of thousands of people from every walk of life have been challenged with these questions, and there appears to be little difference in the human response. Perhaps it varies a little depending upon the language spoken and the subtleties of words as defined by various people, but it seems that human morality is universal and innate.
The development of human moral qualities, as opposed to other creatures who have come into existence through natural selection, is discussed in Intelligent Design – of humans by humans and for humans. That blog post arrives at the conclusion that since pre-modern times it has been women choosing mates based on their conversations with other women which created human beings and adapted them to their surroundings quickly, on an evolutionary time scale. Women by their thousands of generations of carefully discussed selections of the best mates available have created the inborn morality we now have. Men are still choosing their mates primarily on the principles of sexual selection, which is choosing the healthiest, most beautiful women available, for their mates. Very little of males’ choice has to do with morality of their mates, but a considerable part of females’ choice is mediated by how moral a person their potential mate appears to be. Women through their choosing of moral men have created us to be good people.
To return to pushing the fat man off the bridge to save five other people, I would say it depends upon what species you ask in the living world, if that were possible. Considering the havoc that humanity is wreaking on the 100,000,000 other species on Earth, there are probably only a hundred or so other species who would choose to support humanity instead of destroying us. Dogs are probably the only species that would unequivocally choose to support human survival. Milk cows and horses might give a positive nod, but it seems unlikely that those domestic species whose flesh is used for food, such as sheep or chickens, would feel favorably towards humans if they knew they were to be killed and eaten by those humans. Much the same argument for plants, with only a few decorative plants supporting humanity. It would be difficult to find 100 kinds of plants and animals who would support humans, given a vote. Thus, if all the species of the world were given the fat man on the bridge problem, they would vote about a million to one for destroying as many humans as possible. (That’s 100,000,000 who would choose to kill humans divided by about a 100 who would support our continued existence.) By a margin of a million to one they would choose to let the trolley run over the five humans on the track and grudgingly suffer the one human to live.
By the grander natural-ethic the vote is in: Let the fat man live.