Some time ago I wrote about Eastern and Western theodicy, using citations from Augustine and Shankara. :
problem of evil
Here I outline a way of uniting those two ways of looking at the argument from evil by that means of valid knowledge known as anupalabadhi or the non-apprehension of existence (It is accepted in vedanta). A valid means of knowledge according to pramana theory is not reducible to any other. The idea is that if I tell you that there is a book on the table in the kitchen and you go there and see that it's not on the table your knowledge expressed as 'there is no book on the table' is a non-apprehension of the existence of the book. An expectation due to my false belief was disconfirmed by your experience. It is this use of the term 'experience' that gives rise to the view that this knowledge has a perceptual basis which is puzzling as how can we perceive what is not there. The vedantins regard the total knowledge event as beginning with my statement that there is a book on the table. If that were not the case then 'there is no frying-pan on the table' would be an equivalent item of knowledge which it is not. What we are talking about is an absence whose presence was warranted in some manner.
David Oderberg in a paper The Metaphysics of Privation
privation discussing the concept of evil as privative stresses the notion of the absence of what should be there. This knowledge is ontologically grounded as a conjunction between need and absence . The example he gives is of plants and water. To put it in anupalabadhi terms; seeing the drooping plant is a non-apprehension of the existence of sufficient water for that plant.
The state of need is a state of being in potentiality towards something that if
present will actualize the potentiality. It is in this very general sense, I would argue, that salt needs water to dissolve in, a billiard ball needs to have a force applied to it in order to move, and the moon needs the earth’s mass to stay in orbit around it. But it is also in this sense – the concern of the present paper – that plants need water, cats need food, parasites need hosts, apes need social groups, and so on.
If Dharma is things being what they are according to their nature then the falling from that is a matter of immediate recognition assuming that we have a true notion of what that nature is. Evil then is an absence and not something we can know as a positive entity but that is not to say that it is unreal. It is real as privation and the anupalabadhi view holds that this is a basic irreducible means of knowledge.
The incarnations of God are the exemplars of the Dharmic for Hindus:
Whenever there is a falling away from the true law and an upsurge of unlawfullness, then, Bharata, I emit myself.Bhagavad Gita 4: 7,8.
I come into being age after age, to protect the virtuous and to destroy evil-doers, to establish a firm basis for the true law.