The value criterion is...respecting others as ends.
Here are some of the best justifications for a Kantian framework.
Action theory precedes ethics.
Anscombe 58 writes
G.E.M. Anscombe. “Modern Moral Philosophy.” Philosophy, Vol. 33, No. 124 (Jan., 1958), pp. 1-19 Published by: Cambridge University Press on behalf of Royal Institute of Philosophy.
That I owe the grocer such-and-such a sum would be one of a set of facts which would be "brute" in relation to the description "I am a bilker." "Bilking" is of course a species of "dishonesty" or "injustice." (Naturally the consideration will not have any effect on my actions unless I want to commit or avoid acts of injustice.) So far, in spite of their strong associations, I conceive "bilking," "injustice" and "dishonesty" in a merely "factual" way. That I can do this for "bilking" is obvious enough; "justice" I have no idea how to define, except that its sphere is that of actions which relate to someone else, but "injustice," its defect, can for the moment be offered as a generic name covering various species. E.g.: "bilking," "theft" (which is relative to whatever property institutions exist), "slander," "adultery," "punishment of the innocent." In present-day philosophy an explanation is required how an unjust man is a bad man, or an unjust action a bad one; to give such an explanation belongs to ethics; but it cannot even be begun until we are equipped with a sound philosophy of psychology. For the proof that an unjust man is a bad man would require a positive account of justice as a "virtue." This part of the subject-matter of ethics is, however, completely closed to us until we have an account of what type of characteristic a virtue is-a problem, not of ethics, but of conceptual analysis-and how it relates to the actions in which it is instanced: a matter which I think Aristotle did not succed in really making clear. For this we certainly need an account at least of what a human action is at all, and how its description as "doing such-and-such" is affected by its motive and by the intention or intentions in it; and for this an account of such concepts is required.
The volitional nature of agency mandates that reason be universalized to other persons
Christine Korsgaard (C Kizzle in the Hizzle, where Hizzle means Harvard). “Morality and the Logic of Caring: A Comment on Harry Frankfurt.” Stanford University Press. 2006.
But what, if anything, compels us to view reasons as public and universal in this way?15 In my view, part of the answer lies in the role of universal principles in unifying and therefore constituting the will or the self, the role played in Frankfurt’s view by caring. And if the self is constituted by volition, it cannot be assumed to exist in advance of volition. When I will to go to the dentist on the day of my appointment, I cannot be willing a law that my future self should go to the dentist, for whether I have a future self depends on whether that law and others like it are obeyed. If that law and others like it are not obeyed, then my body is, in Frankfurt’s terms, not that of a person but that of a wanton without a self, and no person has disobeyed my law. So I must be willing that an agent characterized in some other way—perhaps as the future conscious subject of my body—should go to the dentist. Minimally, this shows that any maxim that I will must universalize over some group more inclusive than my present conscious self, and that the normative force of the reason I legislate should be public and shared between me (my present conscious self ) and the members of that group.16 Perhaps it is only all the future conscious subjects of my body, but we need some reason why that and only that should be the relevant group, and some of the possible answers to that question suggest that the group should be more inclusive still. For instance, one possible answer is that I must interact cooperatively with the future conscious subjects of my body if I am to carry any of my projects out. But of course it may also be argued that I must interact cooperatively with other rational agents as well, for unless others respect my reasons and I respect theirs, we are apt to get in each other’s way.17 So it begins to look as if I must will universally and publicly— that is, will reasons I can share, not only with the future conscious subjects of my body, but with all rational beings, or at least all with whom I must interact. In any case, I cannot coherently regard my reasons as applying merely to myself. And there may be the beginnings of a route to morality.
Thus the standard is respecting others as ends.
[This framework originally and generously contributed by Sacred Heart AT.]