I am wondering about traditions of ethics which might incorporate naturalism or skepticism.
As far as I understand, the Academic Skeptics, in particular Carneades and Cicero, held that there was no way to know anything for certain, but also held that you could draw conclusions about good and evil from available evidence. They did not think that the existence of a moral good was completely subjective, and they also did not think that the existence of moral goods required a supernatural agent. From the position of the Academic Skeptics, you could derive an ought from an is.
This point of view seems to be consistent with metaphysical naturalism. As the Stanford Encyclopedia of Philosophy puts it,
From the Hellenistic point of view, theology is part of physics. An account of god is part of an account of the natural world (as such, it is unrecognizable as ‘theology’ from the point of view of later theologies). Human beings and their cognitive faculties are natural parts of a natural world. They are organic and functional parts, interconnected with the other parts of the large whole which the universe is. A mind-world-gap (of the kind envisaged in the Cartesian tradition) is inconceivable. Each ‘mind,’ and that is, rational soul, is an integrated physical part of the physical world.
My question is two-fold. First, is my understanding of the ethical position of Cicero correct, and second, are there modern schools of philosophical thought that follow this tradition? To clarify the second question further, are there modern metaphysical naturalists who maintain that questions of good and evil are meaningful?