Animal advocates cannot allow the idea to take hold that only the great apes and certain other "higher" animals are fit to be "persons." Working to change the moral status of the great apes or sea mammals, for example, is a legitimate and important undertaking, but it should not be done at the expense of other animals. Such thinking is not only disconnected from real animals in the real world; it perpetuates the view that beings belonging to species deemed "nonpersons" or "merely conscious" are of lesser, or no, moral significance until or unless, through an institutionalized system of painful, stressful, and demeaning experiments over decades or centuries, some of them might "prove" themselves worthy of being called persons or semi-persons or sort-of-persons entitled to whatever privileges such designations may confer.
It is increasingly being recognized that other animals besides humans have complex mental lives. They not only can suffer pain, injury, and fear, but they are intelligent beings with rich and varied social and emotional lives including decision-making, empathy and pleasure. Based on the wealth of evidence, the great apes in particular – gorillas, chimpanzees, and orangutans – have been singled out for showing a range of mental capacities demanding that the moral boundaries we draw between them and ourselves must be changed. In 1993, The Great Ape Project, edited by Paola Cavalieri and Peter Singer, argued that the "community of equals" should be extended to include "all great apes" (Cavalieri and Singer 1993, 4). Currently, the Nonhuman Rights Project, founded by attorney Steven Wise, is working through the courts to change the common law status of some nonhuman animals from mere "things," which lack the capacity for legal rights, to "persons," who possess the fundamental rights of bodily integrity, liberty and other legal rights to which "evolving standards of morality, scientific discovery, and human experience entitle them" (Wise 2014, 1). While focusing on legal rights for chimpanzees, the Nonhuman Rights Project suggests that expanding the moral and legal community to include these animals could initiate a larger break in the species barrier. For nonhuman animals, Wise says, "The passage from thing to person constitutes a legal transubstantiation."