Inquiry is fundamentally different from stated conclusions, even when those conclusions can be legitimately qualified as knowledge (which is to say, as the products of valid inquiry). One can ennunciate a profound truth without ever even remotely approaching the effort of inquiry needed to earn that truth.
This is one of those "enough monkeys randomly pounding on typewriters" observations; sooner or later even the most capricious and willfully arbitrary of productions will generate something that is "true," "correct," "interesting," etc.  But such "results" are devoid of any philosophical or cognitive interest.
Only when such things are properly and legitimately embedded in a system of justified reasons do they actually amount to something beyond mere barnyard noises.
Logically, the interesting question is not whether a claim is "true" or not, but whether the claim can be justified. "But in the real world it is more important that a proposition be interesting than that it be true. The importance of truth is, that it adds to interest." Truth only adds to the interest when that truth is achieved legitimately, since only then will a thinking being have any reason to suspect it of being true. And the only way legitimacy can accrue to a proposition is if that proposition has been achieved by a rational form of inquiry. Even if miracles, monkeys pounding on typewriters, spectacular intuitions, divine interventions, or the most manifest and bald-facedly stupid luck provided us with a "truth", said truth would qualify as nothing more than vacuous blather until it could be rationally anchored in some logically valid, reasoned form of inquiry as a valid product of that process.
Since the above is true regardless of the particular inquiry, it is certainly true of moral inquiry as well. Having previously addressed myself to the vapid nihilism of "relativism" , it is time now to say a few words about what genuinely rational moral inquiry might look like. My intention here is to gloss a few of the more carefully developed tools of reasoned moral inquiry, but most particularly to gloss them as tools. This is because the title and the focus of this series is Moral Inquiry; not "precepts," "conclusions," "rules," or whatever else one might habitually expect when the word "moral" precedes in the title. And inquiry necessarily presupposes instruments with which to conduct one's investigation. Whether those instruments are physical or purely intellectual in nature, no inquiry can proceed without a set of tools to apply to circumstances as they are found or imagined and test those circumstances in an intelligent and rationally defensible manner .
The primary set of tools to be found in the Western intellectual moral tradition  variously find their principle exemplars in the works of Aristotle, Kant, and the Utilitarians. I will briefly discuss each of these in turn, and then go on to some of their more intellectually effective contemporary representatives. That being said, it is also extremely important to note that when one reads the originals of the above, the difference between inquiry and conclusions can often get blurred. But if one reads the classical exemplars with care, the distinction is still mostly there, and I will certainly emphasize that aspect without qualification here. I will conduct my review in historical order.
I. Aristotle and Living Well:
Aristotle had a great deal to say about everything , a great part of which is now generally agreed to be "wrong" . But Aristotle was often a careful observer of, and reasoner about, the general human condition. And while knowledge has advanced enormously, and technology exploded in unrecognizable proportions from the world of 23 Centuries ago, people are still people, and Aristotle observed them well. Of his various writings on the subject of morality, the Nicomachean Ethics is probably the most accessible .
While the densely systematic nature of Aristotle's thought on this subject is often underappreciated (and largely ignored by me here) and the role of the NE as merely a preface to his work on "politics"  is frequently overlooked altogether, one can still usefully isolate one concept as particularly central to the entire scheme. That concept is "eudaimonia," a term which is sadly translated as "happiness" almost universally in the literature. A much more accurate term would be something like "human flourishing" (which scarcely suffers from more syllables than "happiness"); Aristotle himself often uses the phrase "living well; doing well" as a cognate.
There are numerous criticisms that might be made regarding the specifics of Aristotle's position, but the "nutshell" summary of it is that a "good" world is one in which human beings live fully and completely AS human beings. When we fullfill the "human function" most completely, we flourish as human beings, and thus achieve and express "eudaimonia" in our lives.
As a modality of inquiry, one simply redirects the above ideas toward those questions most relevant to the making of a world in which eudaimonia is a more widely achieve fact, rather than merely a wishfully imagined ideal. That is to say, what sorts of actions and external factors best contribute to "human flourishing" as an ideal made concrete in the world?
II. Kant and the Imperatives of Duty:
Kant is generally the most difficult inquirer in our arsenal for persons of a scientific and empirical frame of mind to read with any sympathy. This is a pity because Kant's importance in contemporary American civil and political life is without parallel. It is not an exageration to say that the American Civil Rights movement of the late '50's and '60's was unqualifiedly Kantian to the bone. I will have more to say on this below and in the sequel.
For Kant the central moral ideas are those of duty and the moral law; duty being the expression of our obligations as determined by the moral law. Kant viewed his moral philosophy as a rational expression of Christian ethics (he was a devout Lutheran his entire life). The moral law, as Kant viewed it, was entirely determinable by "pure" a priori reason, that could settle matters of basic morality by pure thought without any "polluting" references to empirical facts.
Now obviously there are arguable aspects of Kant's original position; even the various "neo-" versions of Kantianism (including that which was the driving core of the Civil Rights movement) do not swallow these claims without qualification. But equally clearly, Kant was on to something, particularly from the perspective of moral inquiry. What ought we to do? What are our obligations, our duties, our responsibilities? Understanding these matters will depend in some robust fashion upon how we see them arising: are these duties emergent properties of the mutual claims of moral agents upon one another (John Dewey)? Or are they expressions of the moral law intrinsic to all persons qua PERSONS (that is, as moral agents and not merely human beings) (Martin Luther King)?
These are questions that call for further inquiry. But to deny that there are objectively valid obligating claims upon us is to license any and every monstrous act and barbarism ever committed. We may not know what our duties are (a matter to be determined by rational inquiry), but to pretend we don't have any is to eliminate even the possibility of moral responsibility in any aspect of human life and action and throw the door open to the most viciously arbitrary behaviors imaginable.
Utilitarianism and the Greatest Sum:
Of all the principal themes in Western moral thought, utilitarianism is the one for which I hold the least sympathy. This undoubtedly colors my assessement below and needs to be taken into account by my less prejudiced readers.
Utilitarianism holds that that action is best which adds the greatest sum of happiness to the world; that action is worst which does the opposite. Unlike the position of Aristotle, which took "happiness" (that is, "eudaimonia") to be a complex matter not easily translated into English, Utilitarians define "happiness" simply and directly as "pleasure." In this way, they hoped to provide an empirical and testable method for determining when things in the world were better or worse.
Broadly speaking, there are two "flavors" of utilitarianism: that which traces its roots to Jeremy Bentham and that which traces its roots to John Stuart Mill. The primary distinction is that Bentham treats all pleasures as of a kind – Opera is of a piece with WWF – whereas Mill very deliberately distinguishes between "higher" and "lower" pleasures (forms of happiness).
Utilitarianism's fatal weakness is that it assumes that it is possible to reduce happiness – hence morality – to arithmetic. Mill made matters unbearably complicated by arguing for the "higher" and "lower" distinction, thus rendering the arithmetic of happiness inordinately complicated. So the overwhelming majority of influential utilitarian moral thinkers (whom we now call "economists") abandoned Mill's notions without a second thought in favor of Bentham's. In order to keep the arithmetic of morality simple, they went one step further and identified "happiness = $$" (Cha-Ching).
To say that the idea that happiness can be reduced to a linear order to which arithmetic principles can be applied is, at the very least, less than entirely obvious. It is not just that some pleasures might be "higher" and "lower"; surely there are some that simply are not comparable? How does one assign measures to different kinds of happiness so as to add and subtract them when those pleasures do not even properly compare or contrast with one another?
On the other hand, surely we must also make some effort to take the sum of happiness – for better or worse – of our actions into account? Certainly it is the case that the classical utilitarians are guilty of gross oversimplifications (and that the majority of mainstream economists who have so grossly oversimplified things even more deserve to be b$...-slapped until they bleed from the eyes). Still it is a vital aspect of any rational inquiry into morality to pose the question – "How does this make people happier overall?" – even as we acknowledge the intrinsic difficulties in making such an evaluation. (Also, one needs to bear in mind that the ethical terms "people," "person" etc. do not necessarily refer exclusively to biological human beings. "Persons" are a moral agents, regardless of their genetic inheritance.) Indeed, it is only as we properly come to appreciate such difficulties of evaluation (which the utilitarians have helped us to come to appreciate) that we can reasonably engage in inquiry into the subject at all.
Presumably it is clear from the above that the only contemporary approaches I would consider worthy of the term "rational" are those that engage some synthetic combination of all of the preceding, and do so in the framework of modes of inquiry rather than announced conclusions. Certainly this seems like the only position that can be rationally defended. All of the preceding have various weaknesses that are not corrected by fundamentalist advocacy. But as tools of inquiry no reasoning person could justifiably cast any of them aside .
On the contemporary scene, the inquiriential approach to moral philosophy has been most emphatically argued by John Dewey. Besides his various works on the subject , the clearest advocate of Dewey's position (relevant to our topic here) in the secondary literature has been Larry Hickman . Dewey himself was a kind of "neo-Aristotelian." This is not a particularly informative label since it also includes persons as diverse as Alasdair MacIntyre and Amartya Sen. But the emphasis upon “human flourishing” (“eudaimonia;” Dewey often used the term “growth”) in some functionally robust manner (that is itself open to further development by means of reasoned inquiry) is certainly an important tool in our cognitive arsenal.
A second contemporary example that has been of enormous practical effect is the form of neo-Kantianism that goes under the heading of American Personalism. The classical representatives of this approach to moral inquiry are people such as Josiah Royce, Borden Parker Bowne and Edgar Sheffield Brightman (who occupied the Bowne chair at Boston University). But of course, while the above theoreticians are important, what makes this movement so notable is its leading activist: Martin Luther King. King went to Boston University to get his Ph.D under the mentorship of Brightman, finishing the job with L. Harold DeWolff after Brightman died.
Brightman's Moral Laws  corrects one of the most crippling flaws in Kant's original work by adding criteria of empirical test and evaluation (which Kant had originally rejected as “polluting” the pure a priori rationality of his system). One of the clearest articulations of these principles can be found in Martin Luther King's famous Letter from a Birmingham Jail . While still open to various nuanced criticisms, King's Letter outlines a systematic method of moral inquiry that is both rationally sound while and predicated on careful and meticulous collection and evaluation of empirical fact.
I will have a great deal more to say about King's rational/empirical approach to moral inquiry in the third part of this series. To conclude this part, though, it is important to emphasize that the philosophically robust moral theory that was the driving force behind the American Civil Rights movement was predicated upon the conviction that moral laws are every bit as objectively real as physical laws. This argument was itself based upon a religious belief in a personal God, but one might wonder if such a belief is logically necessary. If, qua laws of reality, ethics and physics are on similarly objective footing, then why should the objective reality of laws of value and morality – however staggeringly complicated they may ultimately be in their formulation – be any more dependent upon theological claims than the laws of physics?
 All of those terms need to be scare-quoted, particularly at this stage of the discussion.
 Alfred North Whitehead, Process and Reality, pg. 259, The Free Press, New York, 1978.
 As I have argued elsewhwere ( http://www.science20.com/inquiry_inquiry/logic_inquiry ) rational inquiry is not a subset of of science, rather science is a subset of rational inquiry; traditionally, this latter was known as "Logic." As I've already argued in the link in note  there is no rational argument for relativism, so at this point I reject out of hand any attempt to claim that moral inquiry somehow falls outside of the realm of reason and logic. Such a position is devoid of even the possibility of reasoned defense since any such defense is predicated upon its own denial, and is thus grotesquely self-contradictory at its very core.
 An important caveat here with regard to the emphasis on the Western tradition. I do not center my focus here because it is more important than any others, but entirely because it is the only one I am meaningfully qualified to address. In so far as there are other rational traditions in China and India, for example (and there certainly are such) then these traditions also offer important tools for the project of moral inquiry.
 Most of which is actually lost to us. It has been suggested that the bulk of Aristotle's writings available to us are actually lecture notes, rather than polished works. Cicero once wrote that he thought Aristotle's dialogs were more beautiful works of literature than Plato's, yet there is not a single word or punctuation mark of them now extant.
 Although, if one does not try to shoe-horn Aristotle's works on "science" and nature (the latter especially to be found in his work translated as "Physics") into the somewhat narrower paradigm of contemporary science, it turns out that a very large part of what he has to say about "reason" and "the reason for X" remains quite insightful.
 "NE" for the sake of brevity. Different scholars will lean toward different translations. I personally perfer the Hackett edition: Nicomachean Ethics (Terrence Irwin translator), Hackett Publishing, Indianapolis, 1999.
 It is essential to understand that "politics" for Aristotle does not mean wheeling-and-dealing in smoke filled back rooms, but the science of the well-ordered community.
 What auto mechanic worthy of the title would throw away her torque wrench simply because she did not use it every single day with every single job?
 Dewey's book Democracy and Education as well as the middle part of the Dewey and Tufts Ethics are good examples. The latter was republished independently as The Theory of the Moral Life But has sadly fallen out of publication. However, while there are numerous editions of the first book still available new, used editions of D&E as well as either of the latter mentioned works can be had. And both can be downloaded for free from various sources including the Internet Archive: http://www.archive.org/index.php . Consequently, I do not offer any specific editions or publishers here.
 Between them, Larry Hickman and Tom Alexander have redefined our understanding of John Dewey's philosophy. But for the limited purposes of my discussion here, Dr. Hickman's work is of particular relevance. See especially his John Dewey's Pragmatic Technology, Indiana University Press, 1992; and Philosophical Tools for Technological Culture: Putting Pragmatism to Work, Indiana University Press, 2001.
 Edgar Sheffield Brightman: Moral Laws, The Abingdon Press, New York (January 1, 1933); republished by Kessinger Publishing, LLC (June 13, 2008).
 Many copies of this can be found, for example at http://www.stanford.edu/group/King/frequentdocs/birmingham.pdf
Moral Inquiry 2: Tools Of The Trade