Morality and Ethics
One of the most difficult but important areas where people disagree is that of morality. Most people recognize morality to be critically important to people's well being, but if there is a disagreement about what is moral there is no widely accepted definition of morality which would help to resolve that disagreement.
Many people believe that morality is determined by God or some universal power. For this discussion, we will try to find a basis of morality independent of supernatural sources. Religious sources of moral principles are often at odds, and for the time being I am unsatisfied that anyone can demonstrate that their version of the supernatural will is genuine. Understandably those who believe they know what God wants will give these principles priority, but the rest of us can benefit from a secular understanding of morality.
I think some progress can be made on this question by considering the sociology of morality. It seems to be true that human societies have moral systems that they pass down through the generations. The human traits that contribute to this include, I believe, a natural concern for the well-being of other people, and a desire to have others think highly of us. We pass on our moral customs by the way we treat people who we think have behaved well or badly, or, perhaps more often, the way we talk about them behind their backs. We try to be like people who are admired and we try to avoid being like people who are ridiculed.
Further, it seems that we internalize this approval in such a way that we approve of ourselves to some extent on the same basis that others approve of us. If our culture honors people who risk their lives to save others, this will motivate many to take such risks because it will make them feel good about themselves, even if others may not recognize their heroism directly. The fact that such customs vary from culture to culture (such as ritual suicide once practiced in Japan to atone for dishonor) shows we must be learning the values from those around us. The fact that people will sometimes face certain death to preserve a moral principle shows that they must have internalized the principle, since they know they won't be around to hear the praise for their actions.
A moral system such as I have described, is similar to, but different from, a legal system in which there are well defined rules, and procedures for punishing those who break the rules. A moral system is informal and can have vague and general rules, while a legal system must have specific, fairly well defined rules. Legal enforcement is relatively cumbersome, so it is not worth applying to minor matters such as unpleasantness or laziness, but the moral system can still be used to apply some social pressure in such situations. A set of moral values can be used to encourage good or heroic behavior, whereas laws aim mainly at discouraging bad behavior. Laws may also not conform to what we would like to see in a moral system since they are made by legislators who may be unwise or catering to special interests. Thus, we should not expect or demand that the best moral principles we can devise should be totally reflected in our laws.
Given that humans do tend to conform to moral traditions, we might ask what tradition would we prefer that to be? Most people just want everyone else to conform to the traditions they themselves have been raised to believe in, but from a long-term philosophical view, especially if we have an interest in unifying morality across the world, we should not be bound by past tradition. There are two qualities that we want in a moral system: it should be as favorable as possible for our own interests, and it should have as much appeal as possible to others, since the system does us no good if others are unwilling to adopt it also.
In the short term, we cannot expect others to agree on a universal moral system, since they are already committed to the systems they grew up with. In the long run, however, we can hope that the more flexible and philosophical people will see the virtue in a more universal system, and the more who adopt the universal ideal, the less resistance there will be from others who normally tend to follow the lead of others around them.
Given that the basis for morality should be something that not only we, but everyone else would want, the common principle of "the greatest good for the greatest number" seems very appropriate.
A moral system is sometimes called a "social contract". This implies that we all abide by our part of the agreement (we obey the moral rules) with the expectation that others will also conform to the agreement, and we will all be better off. The moral system is a form of cooperation, in which, by helping each other achieve their goals, we all do better than we would by simply maximizing our own gain.
Rather than just telling everyone to always act for the best interests of humanity, we should try to find general principles (like don't kill or steal or destroy property) which are important for the general good. This seems necessary since there are always likely to be individuals who would rationalize harmful actions as being part of some greater good, so when an activity is almost always harmful, we should not leave its moral status up to individual opinion.
Two important questions that need to be addressed are who is included in the group whose good we want to maximize?, and to what extent are people not yet born included in this group? These would relate to the moral issues of animal rights and abortion respectively.
The first question can be addressed fairly directly by recognizing that the moral system is based on cooperation, so it is mainly important to include all those whose cooperation is important to us and are capable of participating in the moral system. Thus, with the possible exception of some primates and marine mammals, it would not make sense to include animals in the "number" when we discuss the "greatest good for the greatest number." This is not to say that animal protection might not be a part of our morality, but it is saying that such protection is ultimately for the emotional and practical benefit of people. Individuals who don't abide by the moral contract are still among the group whose good we try to maximize, but we recognize that sanctions against them may be necessary (ranging from disapproval to imprisonment or even execution) if this would increase the overall good.
It seems prudent to define the group benefiting from the moral system by some strongly defined rule which excludes subjective judgments. If, for example, we decided that certain mentally or physically handicapped people should be excluded, that would open the doors for fanatical leaders to claim that their opposition is insane or in some other way undeserving of human rights.
The need for a well defined moral group relates to the tricky question of abortion. While it is pretty obvious that it is beneficial to women to control their own reproductive systems, and that fewer babies will help relieve the population problem, and that the unborn are not capable of participating in the moral system (yet), we want to make sure that it is valid to exclude this group (the unborn) from those who are participating in the moral system. The key is that there is a clear dividing line between those afforded protection and those who are not. Birth as the criterion is decisive, traditional (age, for example, is calculated from the time of birth), and generally beneficial to society as a whole. It seems, therefore, that abortion can be permitted within a viable moral system.
In summary, while there may not be a natural rule for morality (barring divine dictates), there is a potential to design a moral system, and there is a rational strategy for doing that design.