That, after forty years, I am still trying to describe and justify morality in a way that will be of interest to the general public as well as to philosophers is another example of the triumph of hope over experience. However, that there is even a small chance that this book may help make people aware that they share a common morality and that all of their moral disagreements occur within a larger area of moral agreement makes it worth the effort. Now that people with the most diverse cultural and religious views must interact with each other, it is important for everyone to be aware of their [sic] common morality. It is especially important for people to distinguish morality from religion and to realize that they should not follow the dictates of their religion when these conflict with morality. I am aware—indeed, it is a significant feature of my description of morality—that rational persons need not accept morality as their overriding guide to conduct. However, we now know how much death and destruction arise from allowing any other guide—personal, national, racial, or religious—to overrule the moral guide. Universal acceptance that no other guide can overrule common morality may now be the only way that we can avoid complete disaster.
(Bernard Gert, Common Morality: Deciding What to Do [New York: Oxford University Press, 2004], x)
Note from KBJ: Not to be flippant, but good luck with ISIS. You have to be naive to think that ISIS shares "a common morality" with Westerners. If you can't reason with X and X is bent on killing you, you must kill X first.
