It strikes me that a lot of the thoughts on ethics itt are coming as an argument for the self, and the self alone, regardless of whether that self is self-critical or not. Should we be arguing about what is, or what should be? Now, there is a benefit to being a realist but there needs to be a deeper analysis than simply observing that *you* feel your only motivation is reputation and then extrapolating that everyone else must as well, or simply stating such because you've given up. Immediately this brought to my mind the first lines of the Enchiridion:
Epictetus wrote:Some things are in our control and others not. Things in our control are opinion, pursuit, desire, aversion, and, in a word, whatever are our own actions. Things not in our control are body, property, reputation, command, and, in one word, whatever are not our own actions.
As far as ancient philosophy goes, the Stoics were by and large quite the realists.
Anyway, ethical questions are partly "how do we/I behave" but they are also "how should we/I behave?" The task isn't to figure out what we can all agree upon is reality-as-it-is, but rather how would we like reality to be. While it may seem to a student of history that humanity never changes I think at the same time there is a case to be made for the benefit of holding ourselves to a higher standard, of which we may sometimes fall short. I dislike the trend of treating ethical concerns as if they are context-less math equations of which the subject is the solver. It dehumanizes the Other and by consequence limits our potential as human beings. Civilization is a product of individuals working together to achieve a greater good than they could have without that collaboration, and neither is it as simple as some want to summarize Adam Smith as saying (look out for yourself and it will help everyone the most).
Sophistry, to me, is engaging in these conversations without actually laying your behavior in the future on the line, if you're not attempting to refine your understanding of the world in such a way as to augment your own behavior, you are not engaging in it rigorously enough.
I pointed out Levinas on the first page because I think he gives a radically different perspective than most people do while still staying in the confines of Kantian ethics and German Idealism. Namely, that the ethical question is the "first philosophy" because our approach to the world and the Others we encounter determines the rest of our thought. If we engage the world in a selfish way, placing ourselves as the *prime* end instead of treating all as equally valuable ends then we are operating on the basis of fear and with violence in our hearts. When we approach the Other with ourselves as the prime end we place them into our moral framework and judge them before allowing them (and ourselves to them) the ability to truly represent their value and their ability to augment our potential. Holding this rigid morality of the self then influences our intellectual and business framework such that we limit what we are willing to try and allow in the discussion as true. Further, the need to reify the self's dominance *over* the external and the Other leads, step by small step, to a politics of totality and exclusion. Finally, the fundamental point that makes Levinas unique I think, or more unique than most, is that he asserts that while there is an ethical "right" there is no way to be ethically correct if you force another person to behave ethically correct/right. It is a choice, but there is indeed a correct one, that choice is whether or not to give of yourself to others (which is not to say that you need to be a martyr or anything zealous like that).
@GrammarBolshevik: Could you recommend a good primer essay on Korsgaard? I'm not familiar with her work and her "unconditioned condition" sounds very similar to Mahayana Buddhist philosophy, specifically Nagarjuna's ideas on the tenet of "the emptiness of everything" as in the non-essence of things and beings, where "essence" refers to the qualities inherent to the things/beings *independent* of anything else - basically the argument that nothing has an essence, the "emptiness" of things is the idea that all things are interdependently co-originating, which applies recursively to emptiness itself (which is what strikes me as similar to "unconditioned condition").
@Greyarcher, if you're trying, or at least tried, to work out a normative ethics you owe it to yourself to check out the comparative religion/philosophy scholar Masao Abe's work, specifically the essay "Nonbeing and Mu — The Metaphysical Nature of Negativity in the East and the West" wherein he treats Aristotle's, Kant's and Nagarjuna's philosophies as absolutized frameworks of reality "as it is", "as it ought to be" and it's "emptiness/negation/Mu*" respectively.
*"Mu" is "no" in Japanese.
One last thought, philosophy is about figuring out what it means to live well, don't let that objective get lost in the necessary leaps into abstraction that must be made in its pursuit.