My thoughts about the subject of human-animal differences and similarities began very early in my life. They first became crystallized through reading a church newsletter. This publication carried an article written by the associate minister, who stated: "there is an essential difference between a man and a dog. God created both but only man became a living soul bearing the image of his creator. Furthermore, God with justice or in mercy has made provision for man regarding his eternal dwelling place. Of this I am confident--where man is going--dogs will not be]" Where did this minister derive the authority to make such a dogmatic statement? I asked. Was such a belief part of Christian theology, and if so, why?
At about the same time, another incident stimulated my thinking. One day a Catholic priest who lived next door saw my father and me on the front porch and came for a visit. The family dog was, as always, nearby and the clergyman soon made a remark indicating that animals do not have souls and cannot go to heaven. This judgment sparked a long and memorable conversation, for my father, a surgeon, could not reconcile the injunction by which animals, whose anatomy and physiology he knew so greatly resemble the human could be differentiated from us in that odd way. Over the years, the question keeps returning, though generally in different forms. As our society becomes more and more secularized, fewer people use that particular criterion from the Judeo-Christian tradition to uphold human uniqueness and superiority. Those who currently cite the biblical law of man's rightful "dominion" over the animal kingdom to justify human exploitation are reminded that some scholars have determined that the original word translated as dominion actually means stewardship, not unlimited self-serving control. Nevertheless, in my field research with many types of people interacting with animals, many informants do often cite the Bible as the basis for their behavior toward animals.
The most important determinant of human attitudes toward animals and interaction with them is the degree of similarity or difference that is perceived to exist between people and nonhumans. Opinions and beliefs about this issue vary enormously. It is undoubtedly a question that, at some time in their careers, concerns people who carry out research using animals, for unless there were certain likenesses between our species and the species who are the subjects of research, their work would probably not be undertaken. Mental as well as physical similarities must be perceived to exist. Darwinism implies that "human psychology and animal psychology are continuous." Thus after Darwin one could study animal psychology for what could be learned about humans (Salisbury 185). Yet animals are distinct enough from humanity so that they, and not people, are considered appropriate experimental subjects. Differences are perhaps more generally assumed to be present, and are often taken for granted. But they, too, must be questioned.
Defining the boundaries between people and animals is an old and undoubtedly universal problem dating to the dawn of human consciousness and involving the dilemma of what Thomas Huxley termed "man's place in nature." At various times throughout history, in comparing animals to humans, various species have been regarded in different ways that resulted in great variation in the manner in which they were treated. Notions about the capacities and powers of nonhumans have run the gamut all the way from animals as possessing greater powers and capacities than people and therefore being viewed as gods, to being categorized as totally different in every detail, hence having nothing at all in common with our species. Attributions of superiority and inferiority virtually always accompany the designations. And implications usually follow that involve the appropriateness of exploitation being dependent upon differences.
In the Classical World, humans and animals were considered to be closely related, with plentiful opportunity for crossing the borders between the two. …