Equality requires that two beings are actually equal on some fundamental level. Human beings have certain essential similarities that make them equal. These do not stretch to animals. Human beings are able to distinguish right from wrong while animals have no notion of ethics. We are thus able to consider what kind of a society we want to live in and we are affected when we feel that there is social degradation. Animals, however, do not have this sense. We have fundamental dignity which animals do not. This is clear in the fact that animals do not experience shame or embarrassment, desire respect, or have a notion of self. Furthermore, human beings can consider their future and have particular desires about how they want their life to play out. These are different for every individual. This is why we are concerned with choice and protecting individualism and religion. Animals on the other hand are concerned only with immediate survival. They have only instincts, not individual desires and wants.  For these reasons, we can't consider animals to be equally morally considerable. As for the propositions standard of relevance for the criteria which distinguish animals from humans in any given case, we would argue that the fundamental individuality and humanity of our species is relevant in every case because it makes animal life fundamentally less valuable.