Most moral theories are predicated, at their root, by various assumptions or axioms which in turn cannot be derived independently. That is, there does not seem to be some cosmically significant, absolute grounding for morality that simply and unquestionably exists in the universe. Without this, it might beg questions such as "why is it good to be good?", and the like. I want to firstly present an aesthetic argument - and it cannot be more than that - why we should not be at all troubled by this; secondly, special attention to this issue in the case of morality alone is unwarranted; thirdly, morality deserving of the adjective 'objective' is possible.
In any domain of human knowledge which I can see, if one wants to push back far enough then one is going to eventually back into base assumptions: first principles that cannot be independently determined. We can not derive the validity of our basic logical intuition that contradictions are invalid, for example, and can merely accept this foundation of logic. There always remains certain epistemological, metaphysical, and many other challenges in the background.
Take mathematics, because it is the subject I know best. In any discipline of mathematics, there is an axiomatic core somewhere at its base. For the real numbers, for instance, one can accept a set of axioms for the real numbers and only from that point - with the further assumption of our logical rules of inference - we derive results about there. As Godel showed, even doing complete and consistent formulations using this program is impossible. Any law or theory of physics is itself at its core nothing but an assumption.
We don't, of course, choose these basic assumptions at random. We choose them because either they seem to us to be of such obvious intuitive validity it is hard to imagine they could ever not be true, or, alternatively, because the consequences of the assumption yields so incredibly well with how we observe our universe. That we assume the logical formation of modus ponens as valid is for the former reason, that we assume the speed of light is constant is the latter. Eitherway, we are confronted with the necessity of base line assumptions, determined in as reasonable a way as possible, as part of a larger body of human knowledge.
If it is the case that in all these other domains of knowledge they are ultimately predicated on assumption, why should this be a unique problem for morality? If we can make some small and eminently reasonable moral assumptions for our moral grounding - to which we can subsequently apply all the power of our objective reasoning - is this not only all that we could expect but also entirely consistent with how all human knowledge operates?
Sam Harris introduces the notion of the maximal suffering possible for all conscious beings in the universe. He calls that bad and invites us to do the same. Yes, it is an assumption - just as it is an assumption that we live in a material world - but it is an assumption of such intuitive reasonableness that it seems nearly impossible to consider it not being true. We couldn't have a concept of bad or a word that denoted this concept in our language if it could not apply to such a situation. The broader and standard utilitarian claim one can accept might be something along the lines that increasing the well being of conscious creatures is defined or assumed to be good.
We should recall that this argument is aesthetic in nature. I can only point out that making such assumptions - and indeed having to make assumptions - at the core of morality is neither troublesome or displeasing to me. Further, there seems to be little reason to emphasize the reductionism to base assumptions in morality as somehow special compared to other domains of human knowledge.
Moving on to the semantics question, can we call the above an objective morality? I agree it isn't absolute in the cosmically significant sense, but this does not preclude it from the label "objective". Let us recall the example of mathematics, can we say mathematics is objective? I would say both that it is and further that we must essentially define the word 'objective' so as to include mathematics otherwise it cannot have meaning at all and there is no subjective/objective dichotomy in the universe, everything is the former.
What makes mathematics deserving of the word objective is that one is working logically, rationally and scientifically off of the axiomatic foundations. It is in precisely this sense that I believe some systems of morality are deserving of the term objective themselves. If, for instance, we accept the normative axiom to maximize the well being of conscious creatures, then we can bring all the facets of objective reasoning to bear in flushing out scientifically what actions do just this or what kinds of senses one might mean by 'well being'. While it may be true that this assumption may not be fundamentally derivable without evoking the naturalistic fallacy - as in it isn't an absolute morality - there is such an enormous body of potential to which one can apply objective reasoning to these base assumptions that I am more than content calling it objective morality and setting out to discover what that might be.
Note: This post is at least in part meant as a response to the blog post here.