Without situations there are no stories. Without stories there is no rasa. Therefore, the existence of evil in the world is only to create situations. With no obstacles to overcome, love is unrealized in its scope.
Someone may object: What about horrendous evil?
Evil is not being condoned. Simply it is being said that the greater the evil, the greater the potential for heroism. And love shines all the brighter in the darkness.
This of course requires accepting the world-view of the Bhagavad Gita which says that there is no true death, no true suffering. We are engaged in a play in which the only reality or value is Rasa. raso vai sah.
This of course includes the karma doctrine, which means that everyone answers for their evil. But the law of karma does not answer ultimate questions about evil, for it too faces the problem of infinite regression.
There is a hierarchy of rasas, which are arranged in order from horror (bibhatsa), fear (bhayanaka), anger (raudra), pity (karuna), heroism (vira), wonder (adbhuta), the comic (hasya) and romantic love (shringar). Without evil, without obstacles, none of these rasas can manifest in their purest form. Take, for example, Schindler's List as a tale of heroism in the face of horrendous evil.
I understand heroism to be the primary male rasa, shringar the primary female rasa, with shringara being the overall primary rasa. All rasas are not equal.
I am of course refering to the classical eight rasas here. But if we use Rupa Goswami's model, then the five kinds of relationship in love, or the five kinds of love become the real emotional backdrop in which the other rasas are played out
I am not really saying anything radically original here. Theodicy is always a dicey game to play. For someone who views evil with the conviction of its existential reality, i.e., as a force that actually has or can have the upper hand in absolute terms, in other words, someone who has not completely given up the belief that evil is a winning strategy, the problem is intractable.
Rasa is just an extra dimension to understanding the problem. Rasa is the way we give life meaning. Everyone, including the evil person, is looking for rasa. Rasa includes external sense gratifications etc., but it mostly includes the meaning that we invest in that sense gratification. Rasa is about the story of our own lives. Rasa does require a certain distancing, the ability to see oneself as an objective character, a player in the play.
Great evil also requires this kind of framing of one's one heroism. Like Ayn Rand, who admired a serial killer for his complete indifference to the rules; she thought of him as a kind of superman. Or a Hitler or Stalin, whose acts of barbaric evil were contained within a vision of radical heroism, framed as they framed it.
Although narcissism is not what rasa is about, nevertheless, no one can stop being the center of his own universe. We create ourselves as an author creates the character in a story. But the difference between volitional evil ("the demoniac nature" or pathological narcissism) or the saint, and the common person, is in the strength of the story line.
Yet, we all exist in relationship with the "other" however we conceive of it, through our upbringing and predispositions from other lifetimes and our natural instincts that are a result of our particular species of life. Our lives are about the relationship of self to non-self, the other.
The other is conceived of as either personal or impersonal. This is the difference between love and evil. In Martin Buber's language, this is called "I-Thou" and "I-It". Impersonalism reduces people to objects, Personalism elevates all things, all others, or rather it _recognizes_ all others as the Other, the Divine Conscious Being, present in infinite variety in relation to ourselves.
"I am That" means that I and That are together in the same story. His/her story. We are engaged in a dance. A love story.
The world and the presence of evil are there for the dramatic contrast.