Rationality seems to be something much more complicated than it is. In terms of humans, it is often held on high as the achievement of a highly developed, highly improbable, naturally selected species whose brain is much more evolved than any other. This first element for discourse is already apparent. The source from which these beliefs are derived is none other than the human brain itself. This is not to say that it is not the central necessity of a very complex, incredibly evolved organism: there is no denying that, after four billion years of chance and necessity culminating in our infinitely unlikely existence, we are something strange and wonderful, full of potential for both harm and prosperity. We merely must realize that at the core of this idea, it is actually the brain saying that the brain is the marvel of our universe: something is inherently relativistic in this.
The notion of rationality is strange. It seems more logical that decisions or actions made by any organism would need to be labeled by a large variety of complex factors. The actions of all organisms are always based on how their physiological structure is capable of reacting, what factors of their environment are affecting their actions, the entire history of the organisms experiences, especially with relation to any aspect of the current situation, not to mention how the creature has observed reactions of or learned how to react from others of its own kind, and a multitude of other computations that are likely to complicate the issue more(such as all other outside forces, factors, and other organisms). Basically, how can anyone claim to understand the actions of another organism? There is no way for anyone to be objective when we all have is a subjective perspective.