Why is it wrong to kill babies? Why is it wrong to take advantage of mentally retarded people? To lie with the intention of cheating someone? To steal, especially from poor people? Is it possible that Medieval European society was wrong to burn women suspected of witchcraft? Or did they save mankind from impending doom by doing so? Is it wrong to kick rocks when you’re in a bad mood? Questions of right and wrong, such as these, have for millenia been answered by religious authorities who refer to the Bible for guidance. While the vast majority of people still turn to Abrahamic religious texts for moral guidance, there are some other options for developing a moral code. Bibles aside, we can use our “natural” sense of what’s right and wrong to guide our actions; a code based on the natural sense would come from empirical studies on what most people consider to be right or wrong. Ignoring the logistics of creating such as code, we should note that the rules in this code would not have any reasoning behind them other than “we should do this because this is what comes naturally.” How does that sound? Pretty stupid.
The other option is to develop a moral code based on some subjective metaphysical ideas, with a heavy backing of empirical facts. “Subjective” means these ideas won’t have an undeniability to them; they are what they are and that’s it. Take as an example the rule such as “we should not kill babies.” There is no objective, scientific reason why we shouldn’t kill babies. Wait!, you say, killing babies is wrong because it harms the proliferation of our species and inflicts pain on the mothers and the babies themselves! But why should we care about the proliferation of our species? About hurting some mother or her baby? While no one will deny that we should care about these, there is nothing scientific that will explain why. Science may give us a neurological reason why we care about species proliferation (it will go something like, “there is a brain region that makes us care about proliferation of our species.”), but why should we be limited to what our brains tend to make us think or do?
Subjective rules like these must therefore be agreed upon with the understanding that they are subject to change. Interestingly, some argue that science can answer moral questions because it can show us what “well-being” is, how we can get it, etc. But the scientific reason why we should care about well-being is nowhere to be found. The result is that we can use science to answer moral questions, but we have to first agree (subjectively) that we want well-being. Science by itself cannot answer moral questions because it shows us what is rather than what ought to be. (Actually, Sam Harris is the only one to argue that science can be an authority on moral issues; his technical faux-pas is an embarrassment to those who advocate “reason” in conduct).
But more on the idea of metaphysically constructed moral codes. What properties should this code have, and how should we go about synthesizing it? Having one fixed/rigid source as an authority for moral guidance is dangerous. Make no mistake: there must be some authority on moral questions, but it must be flexible, and adaptable; it must be able to stand the test of time on the one hand, but to be able to adjust to novel conditions on the other. This sounds a lot like the constitution of the U.S. But even with such a document as The Constitution, which has provided unity and civil progress since the country’s founding, there are some who take its words literally and allow no further interpretation; if it’s not written in the constitution, it can’t be in the law, they argue (see Strict Constructionism versus Judicial Activism). These folks also tend to be rather religious (read: they spend a lot of time listening to stories from the Bible; not to be confused with “spiritual” or of religions other than the Abrahamic ones). So while we must have a moral code, it must be flexible (i.e. change with time) and we must seek a balance between literal and imaginative interpretations, just as we do with the US Constitution.
Why and how is a rigid moral authority dangerous? Our authority must change with time because new developments in our understanding of the world must update how we interact with others. For example, if science finds tomorrow that most animals have a brain part that allows them to feel emotional pain in the same way that humans do, we will have to treat them with more empathy; research on dolphin cognition has recently produced an effort by scientists to have dolphins be considered and treated as nonhuman persons. Furthermore, if we don’t explain why we do certain things, we won’t understand why we do them and therefore won’t know why violating them is bad. This unquestionability aspect of God as moral authority or the Strict Constructionists as law-makers is what makes them particularly dangerous and leads to prejudice and ignorance. Our moral code must therefore be based on empirical research, with every rule being subject to intense scrutiny (think of two-year-olds who keep asking, “but why?”).
But why should we have a moral code in the first place? Perhaps if everyone followed a moral code of some sort, the world would have fewer injustices and atrocities. Getting people to follow a moral code of any kind is a completely different issue.