But since Becker wishes to drop the notion of a cosmic deity in the sense of a divine person (within and yet overseeing the physical universe), there is, on the face of it anyway, no basis in his view for values outside of human persons.
There are two problems with this: the first can be overcome by a small adjustment, the second, harder to overcome, can be overcome by creative thinking about social history.
The first problem is that as long as we locate values in persons, it is hard to see how to avoid the anthropocentrism that is part of today's problematic world ideology according to which humans are entitled to be "masters and possessors of [at least terrestrial] nature." Any sensible person, I think, wants to avoid the kind of anthropocentrism that denies to nonhuman life forms anything analogous to the valuing that we find in human life forms. This problem with Becker's theory can be overcome simply by recognizing that while the life projects of nonhuman animals and plants are not exactly the same things as human life projects, they are nevertheless similar enough that the broadening of moral horizons in increasingly wider circles--a process that Stoics recognize as gradually including other humans--can be extended to include individuals of other species, and that as we can empathize with persons in other human communities, so we can empathize with other species in ecosystems quite difference from those with which we directly interact.
The second problem is trickier. Because the Stoic goal is integrated moral agency, the Stoic is committed to autonomy, i.e., to taking as values worthy of respect only those values he or she has rationally chosen to respect. This seems to conflict with the dominant ethical views of our times according to which there are certain principles, the Ten Commandments or the Rights of Life, Liberty, and Property, or whatever, perhaps reflecting God's will, that we have a duty to follow. For all of us who have not chosen to follow these principles, they appear to us the opposite of autonomous, that is, heteronomous--legislated by others and imposed upon us. It seems as if the Stoic is committed to denying that there are any such objective moral truths or values beyond the self-chosen values of the individual.
I do not recommend abandonment of the notion of human rights (though I prefer the more complex balance of rights represented in the Universal Declaration of Human Rights to the bourgeois trinity of Life, Liberty and Property). How can a Stoic make sense of this notion, without granting the non-Stoic the proposition that there are objective values independent of the will or choice of real persons (or other concrete living things) and without granting the existence of a cosmic moral ruler to whom we owe obedience?
The way to make sense of such principles as human rights is to recognize that there there are certain conditions that tend to promote the development of rational agency and therefore of moral development. So-called moral or human rights are basically formulations of conditions that encourage the development of rational agency. The Stoic who has made considerable progress is committed to favoring the development of moral agency in him or herself as well as others (because s/he values the mutual reinforcement of virtue made possible by a community in which all are making progress towards virtue). Therefore, the Stoic generally supports legislation and enforcement of the sorts of rules we call rights. These do not have to be principles etched in the mind of a transcendent or cosmic God that is then somehow "read" by astute human beings. They are moral conclusions to which individuals who have "made progress" tend to come. (Within Stoicism, a person who is making progress is somebody who is moving towards the ideal condition that embodies wisdom and moral virtue, or the fullest development of rational agency, which is essentially the same thing.)
A person who is making progress will pay attention to historic formulations regarding rights such as the U.S. Bill of Rights, the French Declaration of the Rights of Man and Citizen, and the UN's 1948 Universal Declaration of Human Rights. This is an entirely rational thing to do, entirely in keeping with a Stoic's wish to make further progress.
It is rational because even persons not fully wise but only making progress realize that they are not the first persons to enter upon the path towards virtue. Others have trod that path before them and probably traveled farther. In the great generosity of spirit that characterizes such pioneers they have left markers for those who come after. A person who wishes to make progress will not ignore such markers, although she will not necessarily accept all of them and even those she does accept she will not accept uncritically. For example, it is hard to know what to make of one right stated so boldly by the authors of the U.S. Declaration of Independence: the right to pursue happiness. Moreover, a reasonable person today may disagree with, for example, John Locke's conception of a right to property. But historically earlier statements about rights should be looked at as hypotheses to be tested, to see whether or not we should take the values they advocate to be values we endorse all things considered. In this way, today's individuals will "make progress."