["Bulb Light with Tree," by George Hodan, taken from PublicDomainPictures.Net; this image is in the public domain.]
Moral Dogmatism and Moral Relativism both have fatal flaws as perspectives on ethical analysis. The former tends to lead toward deontological systems, and the latter tends to lead to utilitarian systems. Both fail drastically upon close scrutiny.
Deontologies fail for the same reason that Metaphysical systems of analysis fail. In fact, deontologies can be thought of as metaphysical theories of ethics - sets of rules that, in and of themselves, are correct, by virtue of the nature of reality itself. In fact, without a metaphysical grounding, it is not possible, from a philosophical point of view, to posit a coherent deontology, since you would then have no basis to claim that the rules are valid in and of themselves. In other words, if you can't say "reality is such and such," then you can't claim that "this rule is true, because the reality is 'x,'"
Nietzsche and Heidegger roundly demolish the tenability of such deontological and metaphysical theories. Nietzsche points out throughout his work that deontologies conceal a will to power - even from the priests themselves, and that the preachers of these rules actually resent genuine virtue, which arises from individual exceptionalism, not rote obeyance of the moral law. Heidegger points out that undergirding metaphysical systems as such are faulty, because they rely on a particular system of linguistic expression, whereas language is an evolving means of interacting with being, which itself cannot be captured by any set metaphysical system. Being is reality as experience, and objects of being, which is what metaphysics must deal with, are constantly being recast by experience, and language evolves to accommodate that. Thus, any set metaphysical system is necessarily only true from a particular perspective on being; it can never fully capture being itself, since being is itself always in a state of evolution. Thus, deontologies fail because their underlying metaphysical systems fail.
Utilitarian systems likewise fail miserably, and are even easier to deconstruct than deontologies. The underlying utilitarian assumption is that moral systems derive their validity from human and/or animal happiness and/or well-being, and utilitarian systems of morals seek to over-ride deontologies and individualist moral philosophies for some defined moral good.
The best refutation of utilitarianism can be inferred from an analysis of the work of John Stuart Mill - himself a self-described utilitarian. In his book "On Liberty," proceeding from utilitarian assumptions, he points out that freedom of choice is a necessary condition of human happiness and well-being. But this situation leads to a values-based ethic, not a utilitarian one because the necessary corollary of freedom of choice is individual responsibility for choice. When an individual is responsible for their own choices, they must exercise virtue in order to have a happy life. The ability of an individual to recognize when immediate gratification must be sacrificed for future benefit depends on moral virtue - potentially even the kinds of self-overcoming moral virtue that Nietzsche described. Thus, the assumptions of utilitarianism tend to defeat utilitarianism as such. Furthermore, even to posit a defined moral good is highly problematic, since everyone has a different idea of what would be good for them, and in fact, it is not the case that what is good for one person will be good for another, and as Ayn Rand points out, when the good is separated from individual accomplishment, the very basis for the good collapses, since it undermines the very means by which the good can be created.
So, having eliminated dogmatism and relativism as viable perspectives on morals, we are left with values based ethics. I would argue that if you take a values-based ethic seriously, it leads to an ecology of moral systems, because, since it is possible to hold different systems of values, it is likewise possible to develop distinct, valid moral systems.
The philosophical father of values-based ethics can be said to be Aristotle, who, in his Nicomachean Ethics, describes a few kinds of admirable men. These are men with particular kinds of personal virtue; magnanimity, wisdom, leadership, friendship, etc. I find it to be no coincidence that a Greek philosopher was the one to come up with the idea of morality as virtue. Greek culture was a heavily polytheistic one. Polytheism, at its root, suggests an ecology of morals, because different gods represent different virtues which coexist, collaborate, and, in many cases, compete with one another. Nietzsche points out this metaphor very openly in his work, where he scoffs at the idea of Monotheism and reaffirms the idea of Polytheism. Since he is an atheist, we can assume that he is referring to Monotheism and Polytheism as metaphors representing ethical perspectives - Deontology versus Values.
Once we acknowledge that it is possible to hold different perspectives of emphasis on virtues, it follows very clearly that we must accept a plethora of different moral systems as potentially valid. It is important to point out that this is different from the moral relativistic claim, because even though there are multiple possible moral systems, each of these moral systems do yield themselves to scrutiny, because the values themselves are open to scrutiny, and the logical connection between the values and their morals are also open to scrutiny. Thus, not all moral systems can be said to be equally valid, and just as evolution eliminates species which do not array themselves according to the biological reality, the moral ecology eliminates those moral systems which do not array themselves according to the reality of human interaction and survival.
As I delve into this subject in more detail in the future, I will point out how Moral Ecology is not only a necessary consequence of the superiority of values based perspectives over deontologies and utilitarianism, but how an ecology of moral systems, versus a single universal moral system, is actually very necessary to the wellbeing of any social system, and I will analyze it in light of personality psychology, religion, government, and other human systems and attributes.