The Brethren of Purity, a group belonging to Ismailism, are known for highlighting the division between self and otherness. By representing a dialogue between animals humans, they created an opportunity for humans to step outside of their egocentric and anthropomorphic tendencies in order to confront the world of animals as a world completely separate from the world of humans. I think that this is particularly important: without reference to the Other we encapsulate ourselves within the totality which is our culture. It is easy to become entirely engrossed in our constructed world, even to the point where we believe that we are above the realm of animals. The dialogue that the Brethren of Purity engages attempts to question this embeddedness by allowing animals to point out the problems in humanity.
As humans, we seem to forget that we are animals ourselves, and perhaps we are the most evil of them all. I suspect that the fact that we are conscious of our own death, that we are confronted with an awesome fear and confusion when we look down at our mortal bodies, contributes to a willingness to compensate for this deficiency by invoking our rationality as a quality which elevates humankind above everything else. However, it could be argued that it is precisely our rationality which makes humans the greatest oppressors of all. It is rationality that gives us an ability to make choices, but the fact that we can remember and reflect upon theses choices also makes us responsible for our actions. And yet we have made a disgrace of the nature that surrounds us, breeding animals for generations in horrendous conditions, forcing them to copulate at times of our choosing and making mutants out of them. These animals have an ontology of their own, and yet we neglect this ontology and turn animals into objects.
In order to understand exactly how much cruelty humankind has caused, we need absolute otherness to confront us with the injustice of our actions. Animals can do this by coming in dialogue with humans, and providing us with evidence for the suffering we have caused them.