I have a couple concerns with this approach, Quid.
1) Is natural evil really an oxymoron? In the moral sense, yes, as morality cannot exist without rational beings. But things can be good and bad even without human rationality. To take things in an Aristotelian direction, a good tree is one which sinks its roots into the earth and receives abundant nutrients. A bad tree is one that can't manage this effectively.
Things can similarly be good and bad for living entities aside from humans. It is good for a lion to catch a meal. It is bad for an antelope to be that meal. Once we hit human rationality, these lower level valuations develop into full-fledged morality, but the concept exists previously. So why is it the case that the natural world results in processes that create both good and bad outcomes? Why does suffering exist? Referring to all of this as the Problem of Suffering might be more helpful than calling it the Problem of Evil, especially in the pre-human framework.
I think it important to think of telos here. It is 'bad' for a seed to be destroyed, but in the process the plant comes forth. The seed 'dies' so growth can occur, like the process of apoptosis in most organisms. Similarly, a tree that keeps on growing would pass its 'natural' form and become grotesque overgrowth. So a tree that at some point fails to sink roots further is a good tree, in accord with the aim of striving to be an ideal tree. The Mean in otherwords.
Evolutionarily, even more so. For what is the presumed telos in evolution, but reproduction? An animal that never grows old and dies is in competition with its ofspring, acting against its own reproductive success. It is survival of the individual only up to the point where balance between further reproduction, and the needs of its offspring is reached.
Likewise, an Antelope that never gets eaten, would lead to overpopulation, and depletion of its food sources. There must be balance between increase and decrease. I feel like I am quoting The Lion King, by the way.
So sure, maybe you can envision a world where such competing natural cycles and forces do not exist, but that is not the world we see before us. If we wrench out individuals we can say it is 'good' or 'bad' for that one, but is it so for the whole? Even for that organisms' species?
Yet none of this touches Evil yet. There is semantic difference between evil and wrong and bad, at least implicitly. If I punish my son, it is bad for him, bad for me, but is utimately good in order to mould him into a good man. Virtue occurs in opposition to unfettered wish-fulfillment or desire, Licentitas, for you are only virtuous in acting within bounds. This is again a consciousness here required though.
In such a way, a Lion that hunts its prey to extinction is failing being a 'good lion', not only from destroying his own kind's food source, but from wanton destruction of a natural balance or mean. What waxes must wane, or it is imperfect, is not 'good' for that group. Evolution is never about individuals, but kinds; and suffering is an agent of forcing fetters on what is unbounded otherwise. One must struggle to eat, risk being hurt, or else we would just have indolence that perpetually increases itself like a cancer. Perhaps natural suffering breeds 'natural virtue', the awe of the lion, the speed of the cheetah, the parental care, the solidarity of the herds.
Something without 'bad' effects is a creature of wanton destruction. It is a selfish cancer. It absorbs and takes. Good cells must die, must undergo apoptosis when its function is complete. So the question is really what is the goal here? What teleological function is being served? The Final Cause?
2) Is it appropriate in this case to say that natural evil is the result of anthropomorphism? You invoke Stoicism, but I think if anything that would hurt the case for Christianity proper, since Christianity provides an alternative to the pagan philosophies that said either (a) the world is all there is and cannot in and of itself be good or evil, or (b) because the Good is beyond the material, the material must be transcended. Christianity does something different--it says that the world is good. This may be an anthropomorphism, but it seems very clear to me that Christianity is saying quite explicitly, "Your human intuitions are correct. The world is good, but fallen. This is not what it is supposed to be. Any of it."
A fair criticism, yes. But how do we become aware of the fallen nature of the world, except through our own fallen natures? We realise how we should act, but act differently. Humans are hopelessly mired in our own subjectivity, so must of necessity project this onto anything we investigate.
The natural world mirrors our vices - an animal will overeat if given the chance to. It is blundering forth in its own cycles, but they are controlled. To say it is 'in balance' is obviously wrong, as the very fact of animal 'arms races' or such, shows development, but it is fettered change. There is consequence to actions beyond the ideal or mean, a 'natural virtue' of controlled desires.
This is where humans differ. We do suffer our vices, but can overcome or indulge, and through environmental destruction, allow imbalance there too.
So the Stoics tried to subject man to natural controls, live according to fate. The Cynics to deny human controls at all. Christianity says that Man is the operative party here, not Nature. The world is fallen because we fell, otherwise it is good. To the Pagans, we are but of nature and our vices reflect this, a similar position to materialism, that often thus denies vice in entirety. Christianity flips this around, that fallen man corrupts nature, but nature of itself is not corrupt. Hence the Incarnation will renew and restore.
I think my main concern is this:
Can we have much hope that the full Christian picture of morality, particularly in where it departs from pagan thought with its universalism and progressive take on history, is true? Or does the way that evolution unfolds imply that the natural order is the only real order (in more of an Aristotelian than atheistic sense), and Christianity just another empty form of utopianism? Though I've admittedly been in a Puddleglum mood recently myself.
Puddleglum was the last to stand before the Green Lady's incantation. That whole scene is a play on Plato's Cave. The question is if the revelator saying that the shadows are only shadows is correct, or whether the progression of shadows represents true reality. This is where Faith comes in.
The true sceptics and puddleglums are no worse in this though, as you can doubt the progress of the Shadows as much as that there may be something beyond it. It is a matter where you place your faith, but trust in the shadows is really no more secure than in the 'Utopianism'.
With Puddleglum, I'd rather chase the greater thing, though it may turn out a shadow, then just sitting content with what is already a shadow.
As Horace said: Pulvis et umbra sumus - We are but dust and shadow - after all.
