One of the defining characteristics of our age is the radical breakdown of the human/animal distinction. In both the popular media and in scholarly scientific literature, we are shown almost weekly new pieces of evidence suggesting that the barriers separating humans from animals are not as impermeable as we once thought them to be. Behaviors and capacities widely believed to be unique among human beings are increasingly being discovered in varying forms and to varying degrees among a wide number of animal species. There are numerous scientific and anecdotal accounts of such breakdowns: primates passing along novel behaviors through cultural means; elephants grieving and mourning for dead companions; cross-species altruism among various animal species; birds creating elaborate ruses to deceive other animals; squirrels with precise long-term memories; certain primate and bird species demonstrating self-awareness; tool use among a number of terrestrial and marine animals; ravens with stunning capacities for human facial and vocal recognition; confined animals developing novel means for escaping their confinement — and this is just a brief, random list.
Of course, some scientists and critics question whether animals can actually do some of these things and suggest that such accounts of animal behavior are guilty of unjustified anthropomorphism; other critics argue that there are different, multifactorial ways of distinguishing human beings from animals that would answer some of these challenges to human uniqueness. We need not wade into the fine details of these debates here. But we can note that, however the debates turn out with regard to any given claim concerning animal behavior, it is clear that facile attempts to maintain that all human beings are exclusively in possession of some particular trait or set of traits that nonhuman animals lack (language, self-consciousness, tool use, awareness of death, or some other capacity) are becoming ever less tenable.
The fundamental breakdown in the effort to delimit sharply human beings from animals is an important intellectual and scientific development for the philosophers and theorists discussed in this chapter. They view their own work as carrying through on the philosophical implications of this event. And in so doing, they also see themselves as working in opposition to a long-standing, dogmatic tendency within the Western philosophical tradition to deny fundamental similarities among human beings and animals. Now, to state that philosophy has traditionally been dogmatic about animals might seem strange at first blush, for what attracts many people to philosophy is its insistence on rigorously calling into question the dogmas and unthinking prejudices of its time. And, while philosophy's historical reputation for being a leading voice of critical thought is often wholly deserved, on the issue of the distinction between humans and animals and the ethical worth of animals, it has unfortunately and frequently failed to live up to its more admirable ideals. In fact, in many ways, philosophy in the Western tradition has been one of the chief architects in constructing the traditional philosophical and ethical dogmas we have inherited concerning animals.
Consider, for example, one of the founding figures of ancient Greek philosophy, Aristotle. According to Aristotle, animals are best understood as belonging to a naturalistic schema in which they are situated between plants and human beings and as being ultimately (if not entirely) placed in the service of human beings. In Aristotle's schema, plants have life, animals have life and perception, and human beings have both characteristics along with rationality (the Greek word for rationality here is logos, a rich term referring to the capacity for discursive language, reason, and other similar traits). Given this ascending scale of the complexity of life, and given that nature makes nothing "in vain," Aristotle suggests that it is evident "that plants are for the sake of animals, and that the other animals are for the sake of human beings, domestic ones both for using and eating, and most but not all wild ones for food and other kinds of support, so that clothes and the other tools may be got from them."
Animals' lack of rationality also leads Aristotle to insist that they are not genuinely political. Animals are equipped only with "voice" (phone, akin to mere sound or code), which is capable of expressing pleasure and pain but is insufficient for political life. Human beings, by contrast, are capable of rational discourse (again, the Greek term is logos), a capacity that allows them to express "what is beneficial or harmful, and hence also what is just or unjust." As Aristotle goes on to note, "[I]t is peculiar to human beings, in comparison to the other animals, that they alone have perception of what is good or bad, just or unjust, and the rest. And it is community in these that makes a household and a city-state." Aristotle's teleological schema and his claims about animal capacities might appear, from our contemporary perspective, rather outmoded; but his assertions that animals lack rationality and can be seen as resources for human beings have nevertheless dominated the vast majority of subsequent philosophical discourse in the West up to the present.
Another influential discourse on the human/animal distinction is provided by the founding figure of modern Western philosophy, René Descartes. Starting from mechanistic premises, Descartes argues that animals (although alive and capable of sensation) are essentially indistinguishable from machines and that their behavior can be fully explained without recourse to notions such as mind and self-awareness. Animals in his account are complex automata, beings that can react to external stimuli but lack the ability to know that such reactions are taking place.
Cognizant that this kind of mechanistic explanatory framework might sweep up human behavior within its scope, Descartes maintains that even though human bodies can be largely explained using the same premises, we are uniquely co-constituted by a second substance, mind, by which he means rational, discursive, reflective self-consciousness. Proof of the lack of humanlike mind in animals, Descartes argues, is to be found in the dual fact that animals are able neither to "make their thoughts understood" through language nor to solve problems in creative and novel ways beyond the mechanical "disposition of their organs." Given that animals lack mind and a sense of self, experimenting on them (for which Descartes is notorious) and killing them for food pose no ethical problems. As Descartes notes in a letter to Henry More, his position "is not so much cruel to animals as indulgent to human beings ... since it absolves them from the suspicion of crime when they eat or kill animals." As with Aristotle, Descartes's ideas about the human/animal distinction appear rather untenable today, given what we now know about animal cognition. Yet the notion that there is a sharp difference between human beings and animals; that rationality, mind, and self-consciousness are the chief markers of that difference; and that such differences justify the exclusion of animals from ethical consideration are ideas that remain hegemonic in certain quarters today.
Let's consider one final example of traditional, Western philosophical ideas about the human/animal distinction, this one from the famous Enlightenment thinker Immanuel Kant. As is the case with Aristotle and Descartes, Kant denies that animals possess rationality and self-consciousness. Indeed, it is the human capacity to think and act reflectively and rationally that, according to Kant, renders human beings altogether different in "rank and dignity" from all animal and other nonrational beings and that disallows us from reducing human beings merely to the status of instruments to be used for accomplishing our projects.
Kant insists that inasmuch as animals lack autonomy and moral agency, they can be justifiably used as mere instruments, as mere means to human ends, whether in the form of food or as subjects of painful experiments. To be sure, he does not believe that the lack of autonomy among animals licenses human beings to treat them in any way they might see fit. Departing from Descartes, Kant cautions us against unnecessarily cruel treatment of animals, recognizing that "animal nature has analogies to human nature" and that an animal who has served humans well "deserves reward." But his chief concern here is not with what violence toward animals does to animals themselves; rather, his worry is that mistreatment of animals might lead to the mistreatment of other human beings. Hence, Kant argues for the necessity of cultivating "tender feelings toward dumb animals" that will ultimately assist us in "developing humane feelings toward mankind." With Kant, then, we find yet another philosophical framework that seeks to justify the exclusion of animals from the ethical and political community based on their supposed lack of a particular capacity.
This very brief overview of three central philosophers' views on the human/animal distinction illustrates the claim made earlier that many of the major figures in the tradition have offered rather disappointing and uninspiring ideas about animals and their ethical standing. Not only have influential philosophers repeated many of the anthropocentric tendencies of the dominant culture, but in many cases they have sought to provide a rigorous justification for many of our most violent modes of interaction with animals. There are certainly instances in the history of Western philosophy of counter-discourses that challenge anthropocentrism and that question injustice toward animals, so we ought not paint an entirely negative picture of philosophy on the issue. However, it must be said that mainstream Western philosophy has served as more of an obstacle than an aid in helping us to think critically about the human/animal distinction and our attitudes toward animals.
So, how might we begin to break out of the intellectual and practical framework inherited from the dominant discourses in the Western philosophical tradition? The pro-animal philosophers we examine in the remainder of this chapter argue that the path beyond this limited framework is twofold. The first step is to update our ontology of the human/animal distinction. (By "ontology" is meant an account of the basic structure of and relations among beings, of the "basic fabric" of things; in the case at hand, the kind of ontology at issue concerns how human beings and animals are constituted and related.) The second step is to construct an ethics that does justice to this revised view of animal existence, an ethics that doesn't simply seek to justify the status quo but endeavors to correct the dogmas and critical limitations that structure our ways of thinking about and interacting with animals. Let's examine these two steps in turn.
In terms of the human/animal distinction, the philosophers we're examining here all share an ontological perspective influenced by Charles Darwin that stresses the fundamental continuities found among human beings and animals. Rather than maintaining a sharp break between human and animal life (as Aristotle, Descartes, and Kant all do), Darwin places human beings squarely among animals, arguing that it is only human arrogance that would allow us to think we have non-animal, non-natural origins. Darwin is at great pains to demonstrate the phylogenetic continuity of all animals with life as a whole, and he stresses that there is "no fundamental difference between man and the higher mammals in their mental faculties." To this end, Darwin seeks to demonstrate the similar emotional and behavioral lives of human beings and animals, thereby anticipating much of the cognitive ethological work mentioned at the beginning of this chapter. The image of human beings we receive from Darwin is thus one in which we fit squarely within and at the very late edge of a multipronged branch on the tree of life. In biologist Stephen Jay Gould's illustrative phrase, human beings should be seen as a "tiny, late-arising twig on life's enormously arborescent bush."
That we should find such deep continuity among life-forms as a whole, and among human beings and animals in particular, should come as no surprise if we start from an evolutionary perspective. One of Darwin's chief insights is that differences between humans and animals are best explained as differences of degree rather than of kind. There are no huge leaps, abysses, or breaks between species; rather, humans, animals, and all life-forms are participating in the same story of life's evolution, a story that stretches back some 3.5 billion years. Although, as a vestige of the philosophical and religious traditions of the West, we tend to think of "the human" as forming a separate, natural kind with certain essential traits that we uniquely possess, evolutionary biology has taught us to be critical of that way of thinking. To locate traits that are universally distributed among the human species but that do not appear to some degree in other species would be highly unusual; and even if such a trait or cluster of traits was to be found only among the human species, such a situation would be, as philosopher of biology David Hull notes, temporary and contingent. For identity theorists the chief lesson to derive from this evolutionary perspective is that a shift needs to be made away from a parochial focus on human uniqueness toward an understanding of how many basic human traits are found throughout the animal world. Identity theorists do not, of course, argue that human beings and animals are similar or identical in every single respect; but they do insist, on evolutionary grounds, that there is often a deep continuity among human beings and animals with respect to certain ethically salient traits and capacities, such as sentience, cognition, subjectivity, and so on. We will examine a few of these shared, ethically relevant traits in more detail later.
EQUAL CONSIDERATION OF INTERESTS
The second step used to overcome traditional dogmas concerning animals is the deployment of the principle of equal consideration of interests. This principle is common to many ethical frameworks — in fact, many philosophers consider it to be the founding gesture of ethics per se. The basic idea behind the principle is that equal ethical consideration should be given to interests that are relevantly similar, regardless of the individual whose interests they might be. In pro-animal theorist Gary Francione's terms, equal consideration means "treating likes alike." Thus, if an animal has interests (for example, in not being harmed, or not being removed from a particular habitat), the principle of equal consideration of interests suggests that we are called to take those interests into account in our ethical deliberations. The principle also implies that no argument is actually needed for extending ethical consideration to animals; they and all other beings who have interests deserve ethical consideration as a matter of principle. The burden of providing argumentation and reasons lies, instead, with those who deny consideration to animals (or any other individual who has interests). If we were to override or ignore animals' interests, to treat their lives as mere means to our ends (to use Kant's language), this principle suggests that we would need compelling reasons for doing so.
To underscore the point made in the previous section, it is important to remember that pro-animal theorists who work within a neo-Darwinian framework do not wish to argue that human beings and animals are identical in every respect, only that there are certain similarities or identities present among human beings and animals that are ethically relevant. In this case, what human beings and animals both share are interests. Thus, if ethics asks us to take the interests of others into account, and if animals have interests, then we would need some nonarbitrary, compelling reason for not including animals' interests in our deliberations. When we arbitrarily override other human beings' interests — perhaps because of differences in their race, class, gender, or intellectual limitations — this is said to indicate an unjustifiable prejudice (racism, classism, and so on). The same is true if we override the interests of animals simply because they are not members of our species; the unjustifiable prejudice here would be a kind of speciesism, or granting of unjustified privilege to our own species. At bottom, then, the principle of equal consideration of interests is used to claim that beings who are identical or fundamentally similar in ethically relevant ways deserve identical or fundamentally similar consideration. It is primarily this focus on the fundamental identity and similarity of humans and animals along ethical lines that gives rise to the label of identity I am using to describe the pro-animal philosophers of this chapter. Let's now turn to a brief examination of the work of three of the most influential philosophers who employ this approach: Peter Singer, Tom Regan, and Paola Cavalieri.