Another strain in moral philosophy-social contract theory- is equally exclusive of nonhuman animals.According to this way of looking at morality, morality is the product of an in formal agreement among the members of society.Each of us agrees to follow certain rules of the condition that others do the same.The purpose of the agreement is to ensure that all of us act in dependable ways, providing the mutual trust necessary for social cooperation.An important aspect of social contract theory is that this informal agreement is the source of all moral obligation.We have moral obligations to others who have entered into the agreement with us.We have no such obligations to those who are not part of the agreement.Nonhuman animals, who are incapable of entering into contracts, are not part of the agreement.Therefore, we have no moral obligations to them.