What We Owe Our Fellow Animals

Martha C. Nussbaum
March 10, 2022 issue

Can we develop a theory of justice that encompasses nonhuman animals?

Reviewed:

Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves
by Frans de Waal
Norton, 325 pp., $27.95; $16.95 (paper)

Dolphin Communication and Cognition: Past, Present, and Future

edited by Denise L. Herzing and Christine M. Johnson
MIT Press, 310 pp., $40.00

Deep Thinkers: Inside the Minds of Whales, Dolphins, and Porpoises

edited by Janet Mann
University of Chicago Press, 192 pp., $35.00

See All

The world we share with the other animals is

stranger and more wondrous than we humans have
typically realized. Consider three recent scientific
findings:

In 1996 a single humpback whale o! the eastern

coast of Australia was heard singing a new song,
with a dramatically di!erent melodic and rhythmic
structure from the songs the eastern whales had
been singing. Comparing notes, researchers realized
that this was a song that whales o! the Australian
west coast were already singing. By 1997 all the
eastern whales were singing the new song. Whale Nancy Friedland

Nancy Friedland: Night Deer #5, 2022

song, it turns out, changes rapidly, even faddishly, by
imitation.

A group of dolphins in Shark Bay, Australia, were seen swimming around with what
looked at first like odd appendages on their snouts. They were actually sponges, and
scientists later observed the dolphins using them to scrape edible prey loose from the
rough marine floor—apparently to safeguard their soft snouts. Only some of the local
dolphins—mostly females—are “spongers.” They learn the technique from their
mothers and use it the rest of their lives.
In a laboratory experiment at the Max Planck Research Station for Comparative
Cognition on the island of Tenerife, o! the coast of Morocco, both macaws and African
gray parrots learned to take a nonedible token instead of food, trading it later for food
they liked better. Researchers concluded that the birds understood both delayed
gratification and the value of “currency.” “Parrots are capable of making a rational
decision and maximizing the benefit to themselves,” said the lead researcher, Anastasia
Krasheninnikova, noting that the birds performed just as well as chimpanzees in similar
experiments.

It is important for all of us to try hard to understand what scientists have been
discovering. Animals have long been seen as mere property, as “brute beasts.” Now a
revolution in knowledge is revealing the enormous richness and cognitive complexity of
animal lives, which prominently include intricate social groups, emotional responses,
and even cultural learning. We share this fragile planet with other sentient animals,
whose e!orts to live and flourish are thwarted in countless ways by human negligence
and obtuseness. This gives us a collective responsibility to do something to make our
ubiquitous domination more benign, less brutal—perhaps even more just.

But to think clearly about our responsibility, we need to understand these animals as
accurately as we can: what they are striving for, what capacities and responses they have
as they try to flourish. Knowledge will help us to think better about the ethical questions
before us and, especially, to develop a good theoretical orientation toward animal lives,
which can direct law and policy well, rather than, as in the past, crudely and obtusely.

W e humans have cognitive prejudices to overcome. One obstacle is a bias in favor

of our nearest evolutionary relatives. Ape intelligence has long been
acknowledged, but the intelligence of birds, cetaceans, and rodents has been denied.
With this obstacle goes a bias in favor of biology similar to our own: thus even expert
scientists have long denied the extent of the abilities of birds, who have no neocortex
and therefore (many have thought) cannot be very bright. But evolution does not take
just a single route. In the case of birds, “convergent evolution” has produced abilities
very similar to those of apes (tool use, complicated social strategies, the ability to
deceive others) through a totally di!erent biological path.

We are also impeded by what one could call the false lure of language, the tendency to
think that humans are the only creatures with language, and that this sets us utterly
apart from the rest of sentient life. This is a double error. First, it overstates the
centrality of language in human life. Despite what novelists tell us, most of our daily
mental life is not lived in words. Often we think in pictures or tunes, and when we think
in language it is in choppy fragments, far from the prose of Henry James. The second
part of this error is that it neglects the tremendous richness of animal communicative
systems, most of which are still poorly understood. But we can at least begin to grasp
that whale song is amazingly complex as well as beautiful, that the lowly chickadee has a
vocal repertory that experts credit with syntactic combinations, that dolphins, with
their signature whistles, far outdo us in individuality and uniqueness of voice.
Then there is what we may call the false lure of metacognition: the idea that reflexive
self-consciousness is the be-all and end-all of intelligence, and that we humans are
unique in possessing it. Again, this error is double. First, we ourselves reflect about our
own mental states much less than we often claim. Most of our lives are lived with
simpler first-order awareness. (The philosopher Michael Tye has made this case
convincingly in his writings about animals.1) Second, any creature who is capable of
deceiving another creature is capable of metacognition, since to deceive you must be
able to think about the mental state of another. Dogs, squirrels, many birds, and no
doubt a long list of other animals have this ability, which is crucial to survival when you
have to hide your food where your competitors won’t find it.

Behind these biases lies a more general failing, which the Dutch primatologist Frans de
Waal calls “anthropodenial”: the denial that we are animals of a certain type (the
anthropoid type), and the tendency to imagine ourselves, instead, as pure spirits, “barely
connected to biology.” This mistaken way of thinking has a long history in most human
cultures; it remains stubbornly lodged in people’s psyches even when they think they are
examining the evidence fairly. Anthropodenial has led, until recently, to a reluctance to
credit research findings that show that animals use tools, solve problems, communicate
through complex systems, interact socially with intricate forms of organization, and
even have emotions such as fear, grief, and envy. (This is a bait-and-switch: emotions
have long been denigrated on the grounds that they are not pure spirit, and yet humans
also want to claim a monopoly on what they despise.)

Even when scientists and their collaborators avoid these errors, it is extremely di"cult
to get things right about animal lives and capacities. Controlled experiments are very
di"cult to do outside of captivity. And confining large social animals such as orcas and
dolphins in zoos and theme parks is increasingly recognized as unethical. De Waal
believes that with great apes, ethically acceptable research is possible if the facility is
very large, containing a typical habitat and a diverse social group of animals who can
interact freely rather than being stu!ed into cages. He points out that we should be
suspicious of results that are obtained by penning animals up and separating them from
their fellows. If the habitat is built in an animal-friendly way, and if the experiment
involves engaging tasks, he says, the animals will come.

But even if this is right for apes, it cannot be the solution for animals such as elephants,
dolphins, and whales, since for them a normal social life involves not just a large social
group but also a vast expanse of land or sea in which to move. (A possible exception
might be a group of dolphins who happen to stay in a naturally partly enclosed coastal
bay, and these settings have proven to be prime sources of research opportunities.) But,
apart from its ethical problems, captivity distorts natural behavior. In most cases, then,
observers must go out and live near the animals they study for extended periods of time,
learning how to become accepted as nonthreatening, perhaps even as honorary
members of the group. This has produced excellent results for studies of animals as
diverse as African parrots, elephants, and baboons. But what about whales? The closest
scientists can come to “living with” them is shown in Hal Whitehead and Luke Rendell’s
The Cultural Lives of Whales and Dolphins in a photo of the small yacht on which these
two intrepid scientist-sailors spend half of each year, aided by technology to record and
photograph whales underwater. It is also impractical for humans to “live with” most
birds, although here, too, audio and video recording have opened new doors.

T he books discussed here vary greatly in style. Carl Safina, the author of Becoming
Wild: How Animal Cultures Raise Families, Create Beauty, and Achieve Peace, is a
science writer who accompanies research scientists as they work; he writes with grace
and flair. De Waal’s Mama’s Last Hug: Animal Emotions and What They Tell Us About
Ourselves is the latest in this major scientist’s series of eloquent explorations of animal
lives. Deep Thinkers: Inside the Minds of Whales, Dolphins, and Porpoises, edited by Janet
Mann, is a gorgeous picture book at the very highest level, in which leading research
scientists tell us about the current state of knowledge in their subfields. Denise Herzing
and Christine Johnson’s Dolphin Communication and Cognition: Past, Present, and Future
is a collection of cutting-edge scholarly articles, accompanied by a first-rate introduction
to the field’s ethical issues by the philosopher and dolphin expert Thomas White.
Whitehead and Rendell have written a dense, rigorously argued, and witty treatise about
cetacean culture that manages to be both scientifically important and accessible to
nonexperts who have genuine curiosity and are willing to work hard.

All these books show how scientists confront the limitations of their research with
ingenuity and imagination; but they also acknowledge, Socratically, their own
considerable ignorance. Here’s where we are: the animal world contains a kaleidoscopic
diversity of life-forms and types of cognitive awareness. Animals have evolved to be
extremely good at survival strategies, and these strategies vary with the environment, as
they must. As de Waal puts it in a preface to a book about birds by Nathan Emery:

We used to think in terms of a linear ladder of intelligence with humans on top, but
nowadays we realize it is more like a bush with lots of di!erent branches, in which each
species evolves the mental powers it needs to survive.2

Animals who look sort of like us are stranger and more complicated than we thought,
and those who look nothing like us (whales, birds) turn out to have some of the most
sophisticated cognitive equipment. Nor are humans “at the top” of any ladder. Some
animals have senses that we utterly lack. Many birds have a strong sense of magnetic
fields and, through that, can navigate the world with an accuracy of which we can only
dream. Dolphins have the capacity for echolocation, a form of perception akin to sonar,
which can inform them not only of the contours of an object but also of its insides. (One
dolphin researcher was informed of her own pregnancy by a dolphin, who noticed
something strange inside the woman’s body before the woman herself had thought to
get a test!3)
 New York Public Library

As for emotions: so long as researchers thought of emotions as subjective feelings, it was

di"cult to get evidence for fear and grief in other animals. (The same problem, of
course, impedes the ascription of emotions to other humans to whose subjectivity we do
not have direct access, but nonphilosophers rarely notice that problem.) Now, however,
in neuroscience and evolutionary biology, emotions are understood as important pieces
of animal survival equipment, with clear links to behavior. In e!ect, they are ways of
processing information about how a creature’s important goals are being met in the
world; they ascribe salience or importance to objects to which creatures are attached.

The ancient Greeks and Romans knew all this: Aristotle, and especially the Greek and
Roman Stoics, devised rich theories of emotion based on these ideas, and modern
philosophical theories often allude to a rediscovery of these ancient insights, which had
been dislodged by more recent mechanistic philosophies.4 The Stoics argued that all
emotions involve thoughts about the great importance, for our lives, of external objects
that lie beyond our control. (For this reason they concluded that we should get rid of
emotions by ridding ourselves of these attachments, sources of so much pain; but we
can keep their insightful analysis while disagreeing with their recommendation,
contending that excising these attachments impoverishes our lives.)

A turning point came with the remarkable work of the neuroscientist Antonio
Damasio, who had the luck of treating a patient named Elliot, formerly a
successful businessman, whose brain had been injured (by necessary surgery for a
tumor) in the area that seems to be the seat of emotions. After the surgery, he simply
had no emotions at all. Elliot was highly intelligent. He could perform complicated
calculations. But he had no clue what to do with himself. The world provided him with
no guidance. Nothing stood out as more significant than anything else. So he dithered
and was basically incapable of action. Damasio knew that the same problem had been
observed in Phineas Gage, a nineteenth-century railroad worker who was injured in the
same region of the brain after an errant iron spike pierced his skull.
What emotions do, Damasio concluded (along with numerous cognitive psychologists),
is give us a map of goals and meanings so that we can chart our course through life. But
of course all animals—apart from those Aristotle called “stationary” (sponges, corals)—
need that ability. De Waal concludes:

As a result of Damasio’s insights and other studies since, modern neuroscience has ditched
the whole idea of emotions and rationality as opposing forces, like oil and water, that don’t
mix. Emotions are an essential part of our intellect.

By “our” he means the wide range of animals he considers in the book, from
chimpanzees, bonobos, and monkeys to elephants, dogs, and parrots, and humans. (His
inclusive treatment of animal emotions is not an innovation: by now there is a long list
of studies of animal emotions, by both research scientists and top science writers,
including an earlier book by Safina.5)

Perhaps these books’ most fascinating new insights are those into animal social
cognition and social complexity, which in many cases include learning that is culturally,
not just genetically, transmitted. Safina clearly describes the evidence for the cultural
transmission of knowledge in three very di!erent species: sperm whales, scarlet
macaws, and chimpanzees (known already through de Waal’s pathbreaking work on
both chimps and bonobos). Sometimes the evidence comes from controlled
experiments. Where that is not possible, scientists rely on contextual variation, cases in
which two genetically similar subgroups display di!erent strategies in response to
di!erent environmental challenges. Such conclusions must be reached one case at a
time, showing rigorously that a given behavior could not have been produced by genetic
transmission alone.

Whitehead and Rendell argue both skeptically and rigorously for instances of cultural
transmission in marine mammals, often using illuminating comparisons to birds.
Defining culture as “information or behavior—shared within a community—which is
acquired…through some form of social learning,” they proceed to sift through the
evidence that whales and dolphins demonstrate cultural learning. Despite their rigor and
skepticism, they find quite a lot. After all, they conclude, staying alive in the ocean is
tough, and these mammals use the group as an important mechanism of survival.

A clear case is whale song, where change passes from one group to another through
imitation. (Birdsong, they note, is also largely cultural.) Similarly cultural are instances
of tool use, such as that dolphin group’s use of sponges to help its members forage on a
rough ocean floor. (Again, some birds also learn tool use culturally, such as the blue tits
who learned how to open the foil caps of old-style British milk bottles to drink the milk,
and then taught this behavior to other tits.)

More generally, the cohesion of many groups of whales (including sperm whales and
orcas) and dolphins clearly involves social learning and communication. Whitehead and
Rendell’s book and the essay collections edited by Mann and by Herzing and Johnson
describe in great detail the process by which scientists have learned about these social
networks and established that some aspects are clearly cultural. With dolphins, many
controlled experiments have been performed. With whales, the typical process is to look
for contextual variation in behavior and communication among biologically similar
groups.

Here’s something I was surprised to learn: the part played by menopause in the lives of
orcas. Orca society, like sperm whale society, is matriarchal. But what is the use of
females who are too old to be fertile but are still healthy? Both orcas and pilot whales
first give birth at age ten or so, cease giving birth in their forties, but live into their
eighties. Why? Scientists currently believe that the presence of healthy older females,
not depleted by recent pregnancies or distracted by nursing, has a knowledge-
transmitting function: they can, in e!ect, serve as the group’s resident professors! “It
seems,” conclude Whitehead and Rendell, “that menopause may be wrapped up with
culture and has evolved in both humans and the matrilineal whales because cultural
information is so important in both.”

T he new learning about animal lives and their complexity has large ethical
implications. At the most general level we must face up to the fact that many, if not
most, animals are not automata or “brute beasts” but creatures with a point of view on
the world and diverse ends toward which they strive—and that we interfere with these
forms of life in countless ways, even when we do not directly cause pain. We deplete and
reduce habitats, we fill the seas with plastic trash that often becomes lethal food for
whales (once ingested it remains undigested, filling up their stomachs until the whales
can no longer eat nutritious food), we disrupt marine mammal life by noise pollution
(military sonar, air guns used by oil drillers to chart the ocean floor), we build brightly lit
skyscrapers into which small birds crash—and the list goes on and on. If injustice
involves wrongfully thwarted striving—and I think that’s a pretty good summary of the
basic intuitive idea of injustice—we cause immense injustice every day, and injustice
cries out for accountability and remediation.

Even when we think that we are taking care of animals, so often we do it unethically.
Many companion animals are given insu"cient exercise and cognitive stimulation. But
it’s far worse for animals taken from their environment and kept in zoos. There are some
animals who can ethically be kept in some type of captivity: for example, de Waal’s large
island research colony at Arnhem, with room for a large social group of apes, free to
roam outside of cages. Most apes in zoos, however, are cut o! from their basic form of
highly social life.

Elephants and whales can never be ethically kept in captivity. An elephant life involves
hundreds of miles of walking and a large matriarchal herd. Whales, too, need wide
expanses of open ocean and a group in which to learn their identities. When a young
orca is snatched from its pod and put into a marine zoo, this is not just an impoverished
environment. It also cuts the orca o! from learning how to be an orca. Tilikum, the orca
central to the documentary film Black!sh (2013), was no more able to learn the culture
of his species than were the rare feral children who had been raised without human
nurture. His pathological behavior (killing his trainer) should have come as no surprise.

Once we realize that these animals are not genetically programmed mechanisms, but
learn by acculturation, we see that they cannot grow up healthy without their groups.
Similarly, the killing of a postmenopausal orca grandmother cuts o! knowledge that is
needed for younger generations to survive and be themselves.

The test for whether captivity is ethical should always be to ask whether creatures can
exercise their characteristic activities in attractive and typical surroundings. Captivity is
potentially acceptable for many fish, for most smaller animals (always provided that the
environment is spacious and well structured, permitting characteristic group
interactions), and some birds (parrots, for example, don’t need a large group and prove
content to live in pairs).

I f humans are to make progress in helping animals flourish—and removing the many
barriers to flourishing that we have long maintained—we will need, in addition to
good science, courageous activism. But we also need an ethical theory to direct our
e!orts in policy and law. Until recently, the available theories have been pretty crude and
unhelpful.

One theory that is widely used in law I like to call the “So Like Us” approach, associated
with the lawyer Steven Wise and his Nonhuman Rights Project. It seeks the status of
“person,” and associated rights, for a small group of animals whom judges are likely to
view as close to humans on the grounds of that similarity. The focus has typically been
on apes, although elephants have recently been included.

Wise is no dogmatist, and his use of the “So Like Us” idea is more strategic than
theoretical, but it is surely a mistaken theory. First, it neglects the sheer complexity and
strangeness of animal lives, focusing on facile associations rather than learning as much
as possible about animal sentience and sociability. More importantly, though, similarity
to humans cannot by itself be a good reason for an ethical conclusion. This focus on
similarity neglects the many surprising things animals do that are totally unlike human
abilities and activities: echolocation, flight using an internal magnetic field sensor,
complex forms of cultural learning that involve only females.

If we search for a more adequate theoretical basis, what the new learning immediately
suggests is that we might begin by looking at what matters to each animal. Surely the
reason not to keep an orca isolated in a pen is not that humans don’t like isolation (after
all, some do!) but the fact that orca society is intensely social, and crucial learning is
transmitted through group interactions. The “So Like Us” theory short-circuits
curiosity, when the question we ought to ask is what each creature strives for and needs,
and how various arrangements made by humans foster or impede that striving.
Far more helpful is the Utilitarian approach pioneered by Jeremy Bentham in the
eighteenth century and championed today by Peter Singer, one of the best philosophical
advocates for reform in animal treatment. This theory holds that pain is the one bad
thing and pleasure the one good thing. Bentham thought pain was single, varying only in
intensity and duration, and Singer has recently moved close to Bentham in this view.
Benthamites see animal lives as, basically, containers of pain or pleasure and seek to
maximize pleasure and minimize pain.

Utilitarianism looks like a beginning: if we were only to get rid of the torture to which
we subject animals daily—through the manifold harms of the meat industry, through
habitat destruction, through lethal pollution—we would improve animal lives
considerably.

Still, Utilitarianism has many shortcomings—most of which were already seen by John
Stuart Mill. First, it lacks curiosity about the diversity of goals each animal life pursues.
An elephant in a zoo enclosure, or an orca in a pen, might possibly lack pain if well cared
for, but she would still lack free movement over a large terrain and the company of a
large social group. Each animal needs many di!erent things, and di!erent animal
species need di!erent things. Furthermore, Utilitarian theories neglect the individual
creature (whether human or nonhuman), pursuing an aggregate of pleasure or well-
being and treating the individual as a container of goods that contribute to that
aggregate. Finally, the theory neglects agency, treating animals as vessels of experience
rather than active beings who move toward what they want and need.

P eople who care about animals have therefore increasingly turned to a theory known
as the Capabilities Approach (CA), developed in di!erent ways by me and by the
economist Amartya Sen. In the CA the central question is “What is this creature actually
able to do and to be?” The theory—which got its start in development economics—
focuses on the ability to select valued activities and to avoid the frustration of choice.
Sen uses the approach for comparative purposes: it is more illuminating to compare
capabilities than to compare utilities, or GDP per capita. My version is di!erent: it
creates a theory of basic justice, focusing on the duty of nations to create su"cient
opportunities for significant activity in some particularly important areas, including life,
health, bodily integrity, emotional health, choice and a"liation, and leisure time. With
valuable input from a group of younger members of the international Human
Development and Capability Association, I have recently been developing my theory
into a theory of justice for nonhuman animals.6

The theory is, of course, species-specific. For each species, it must identify the most
significant activities and a minimum threshold beneath which we should judge an
animal’s life to be unjustly thwarted. It must also allow plenty of room for the individual
choices of di!erent members of the species. And then we must propose strategies for
achieving that threshold in law and policy.
Recently, for example, I have used my theory to argue in an amicus brief that Happy, an
elephant kept in a small enclosure without any elephant company in the Bronx Zoo,
should be transferred to an elephant sanctuary, where she could enjoy greater mobility
and social interaction. (The case has not yet been heard.) And I have also pointed to
legal decisions that already follow what my version of the CA recommends without
using it explicitly, just by showing a concern informed by knowledge of animal behavior.

A favorite case of mine is Natural Resources Defense Council v. Pritzker (2016), in which
the Ninth Circuit Court of Appeals invalidated the US Navy’s sonar program on the
grounds that it violated the Marine Mammal Protection Act by impeding several
characteristic marine mammal activities—foraging, breeding, migration—and induced
stress responses. This novel interpretation of the statute is exactly what the CA would
recommend. Even though the sonar did not cause physical pain, the fact that the whales
were unable to live their characteristic lives was su"cient to make it a violation of the
statutory requirement to avoid “adverse impact” on marine mammal species.

I’ve been happy to see that scientists grasping for an ethical approach to complement
their work have been turning to the CA. Thus, for just one example, in the Herzing and
Johnson collection, Thomas White’s essay recommends that approach to marine
scientists (citing some of my earlier work), and argues that it fits well with their
discoveries. He writes:

The best approach should be species speci!c and grounded as much as possible in facts….
The concept of the “flourishing” of a being (and its relationship to the concept of moral
rights) forms an appropriate foundation for an ethical standard.

And he shows in detail how the approach can be used to argue for an end to whaling as
currently permitted under international law, for an end to captivity for both whales and
dolphins, and for restrictions on sonar and other disruptive human activities. I whole-
heartedly agree.

Because White was asked to guide these scientists in the area of ethics, I am hopeful
that they may use the approach in their future work. Whitehead and Rendell, who
visited a law and philosophy seminar I was teaching at the University of Chicago, have
grown enthusiastic about the CA, saying it shows them a new way of thinking. And at
least one animal welfare organization has used the CA as its central theory: Friends of
Animals, an organization doing legal work for both domestic and wild animals. Its
Wildlife Law Program, which until recently was directed by the lawyer Michael Harris,
currently uses the CA in legal work on behalf of wild horses, elephants, American bison,
and many other creatures.

Achieving even minimal justice for animals seems a distant dream in our world of casual
slaughter and ubiquitous habitat destruction. One might think that Utilitarianism
presents a somewhat more manageable goal: Let’s just not torture them so much. But
we humans are not satisfied with non-torture. We seek flourishing: free movement, free
communication, rich interactions with others of our species (and other species too).
Why should we suppose that whales, dolphins, apes, elephants, parrots, and so many
other animals seek anything less? If we do suppose that, it is either culpable ignorance,
given the knowledge now so readily available, or a self-serving refusal to take
responsibility, in a world where we hold all the power.

Martha C. Nussbaum
Martha Nussbaum is the Ernst Freund Distinguished Service Professor of Law and Ethics at the
University of Chicago, with appointments in the Law School and the Philosophy Department.
(December 2022).

1.
See Michael Tye, Tense Bees and Shell-Shocked Crabs: Are Animals Conscious?
(Oxford University Press, 2017). ↩

2.
Nathan Emery, Bird Brain: An Exploration of Avian Intelligence (Princeton University
Press, 2016). This book is an excellent resource, along with Jennifer Ackerman, The
Genius of Birds (Penguin, 2016) and The Bird Way: A New Look at How Birds Talk,
Work, Play, Parent, and Think (Penguin, 2020). The Bird Way was reviewed in these
pages by Robert O. Paxton, February 25, 2021. ↩

3.
See Thomas White, In Defense of Dolphins: The New Moral Frontier (Blackwell,
2007). White heard the incident from researchers at the Dolphin Research Center in
Florida. The dolphin was herself pregnant and was fond of comparing her belly
with that of a visibly pregnant researcher. She later made the same gestures to a
researcher who did not know that she was pregnant and subsequently discovered
that she was. ↩

4.
For example, the great cognitive psychologist Richard Lazarus, in Emotion and
Adaptation (Oxford University Press, 1991), says that scientists are just now
attaining the insights contained in Aristotle’s Rhetoric. And both I and other current
writers allude to the Stoics: see Robert Solomon, The Passions: Emotions and the
Meaning of Life (Hackett, 1976); and my Upheavals of Thought: The Intelligence of
Emotions (Cambridge University Press, 2001). ↩

5.
Beyond Words: What Animals Think and Feel (Henry Holt, 2015); reviewed in these
pages by Tim Flannery, October 8, 2015. Flannery’s review also discusses
Whitehead and Rendell’s The Cultural Lives of Whales and Dolphins. ↩

6.
I sketched this extension in my Frontiers of Justice (Harvard University Press, 2006),
and the fully developed version will appear in my Justice for Animals: Our Collective
Responsibility, to be published by Simon and Schuster in December. ↩

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