The very essence of the noble and heroic in human society is the protection of, and devotion to one's "tribe." But when the actions undertaken in this effort bring into doubt the survival of civilization, the survival of humanity itself, or indeed the biological well-being of the Earth-surely then we have crossed some line. Given our tribal nature, this line is one that we have neither been designed to recognize nor have evolved to confront. A pressing challenge for our age.
