Ethical naturalism is the only authentic metaethical philosophy.

===The Primacy of Want=== My opponent argues that justifiable actions are best reduced to the "basic units of motivation" by ethical agents because "the ONLY good reason to do something is because you want to". In effect, my opponent has conflated the meta-ethical requirements of goodness with the psychological presuppositions of action. Surely it is obvious that in order to do something on one's free will, one must want to do it. But where does my opponent make the jump between that and the proposition that what one wants to do is the best reason to do it? My opponent claims that even if there are better reasons to do something, mere want and desire are the only epistemically available options for discerning good. However, doesn't this more add to the theory that what justifies action simply can't be reduced to psychological states or if this standard does exist that it is simply epistemically elusive? It appear to be special pleading to make the jump simply because my opponent wants there to be an objective state of justifiability and can't seem to find it. ===Evaluative Calculus=== Here, my opponent makes the concession that desire does not in itself imply goodness, evolving his position to be that only wants can be the basis of justifiability but not all wants may serve this function. In this argument, my opponent offers a way of deciphering between which wants are good and which are not, effectively offering a standard from which to weed out bad wants. As the standard for wants, my opponent offers social responsibility and needs co-aligned with personal valuations. My opponent argues that out of all of our near infinite amount of wants, those which take our own interests as well as the interests of others into consideration will yield the just course of action. However, far from an objectively "evaluative" calculus, the "inner practical calculus" that my opponent describes isn't objective at all. At the end of the day the correct course of action (according to my opponent's conception of ethics) rests on one's inner weighing of their own personal values (therefore losing the title of ojectivity) as well as their own epistemically unverifiable opinions on the valuations and needs of others (therefore losing the title of epistemic verifiability). There is no way for me to know what you or anyone else truly values, only my own values can be known for sure. So my opponent's inner calculus not only isn't objective (as it rests on personal valuations which are definitionally subjective), but is also epistemically incoherent. ===A Practical Imperative=== My opponent makes two mistakes in this point. The first is that my opponent posits a state of affairs which are self-justifying purely on the grounds that we aim for that end. This is a mistake which has been at the core of my opponent's case and I will point it out again here. My opponent again makes the fallacious conflation of one's subjective psychological desires and something that is metaphysically good in an objective sense. This is an unwarranted jump by my opponent. For one's personal subjective valuations can by definition not be an objective standard since it rests on subjective whim. ===Morality and Social Norms=== I am in full agreement with my opponent that many social norms are not self-justifying and many rest on purely arbitrary grounds i.e. discrimination against homosexuals, women, etc. However, I fail to see how this point in any way furthers the case for ethical naturalism and I implore my opponent to explain how it does. ===The Point of Morality=== This is more of a lesson in descriptive ethics than an argument in favor of any meta-ethical system (though I'm not complaining as this is an incredibly fascinating topic). It is true that humans have evolved to support certain norms over others (recripricol altruism for example) but that doesn't lend credence to any specific ethical systems authenticity or soundness. For as my opponent himself mentioned, biological fitness and eugenics are also adaptable traits which have led to events which my opponent would not describe as particularly ethical i.e. the Holocaust. So it doesn't appear that this point (like my opponent's previous point) helps with his case. ===Supernaturalism=== I concede to my opponent the ethical naturalist tenet that "Supernatural/metaphysical claims are unacceptable bases for ethical claims." ===Directing Harmony=== My opponent here argues that human morality has with it the goal of social harmony. I agree with this in a sense. It is true a la descriptive ethics that morality (conscience, evolutionarily advantageous feelings) evolved in order that we as humans would better be able to survive. Again, reciprocal altruism would seem to be moral evolutions crowning achievement. However, my opponent has provided no bridge between what is evolutionarily advantageous or reinforced to what may be described as metaphysically good. ***Refutation of the Pro Case*** Wants, Needs of Others and Epistemic Incoherence My opponent has succeeded in proving this point insofar as he can show one can have an epistemic basis in deciphering when the actions which he argues are moral are attained. However, this is not the case (my opponent is also wrong in what actions he defines as moral but that is a different matter). As I pointed out earlier, taking the desires, needs, and wants of other people into account as the deciding factor of ethics is epistemically impossible as one cannot intimately know the various needs and wants of others. As my opponent even admitted, we can't even be sure to know what is in our own best interest. Therefore even if one grants to my opponent his argument for what makes actions moral, the verifiability factor makes it impossible. If these propositions are true, we can never know them and thus my opponent's argument cannot be epistemically proven or practiced.