Animal Liberation: A New Ethics for Our Treatment of Animals is a book written by Australian philosopher Peter Singer in 1975. This book is widely seen as the first important statement of ideas in the animal liberation movement. Singer did not use the idea of rights when discussing how humans and nonhuman animals should be treated. Instead, he followed the ideas of Jeremy Bentham and argued that animals’ interests should be considered because they can feel pain. He believed that the idea of rights was not needed to support this view. In the book, Singer introduced the term "speciesism," which was first used by Richard D. Ryder to describe the unfair treatment of animals. A new version of the book, Animal Liberation Now, was published in 2023.

Summary

Singer explains that animal rights are different from human rights, stating in Animal Liberation that "there are obviously important differences between humans and other animals, and these differences must give rise to some differences in the rights that each have."

In Animal Liberation, Singer opposes what he calls speciesism: treating beings unfairly because of their species. He believes all beings that can feel pain deserve equal consideration, and treating beings less kindly because of their species is as unfair as treating people unfairly because of their skin color. He argues that animals' rights should depend on their ability to feel pain, not their intelligence. He points out that while many animals have lower intelligence than the average human, some humans with severe intellectual challenges have similar or even lower mental abilities. Additionally, some animals, such as primates, have shown signs of intelligence, like learning parts of American sign language or other symbolic languages, sometimes at levels comparable to young human children. Therefore, intelligence should not be used to justify giving nonhuman animals less consideration than humans with intellectual challenges.

Singer suggests that the most practical way to address these issues is by choosing a vegetarian or vegan diet. He also criticizes the use of animals in painful experiments (vivisection) unless the benefits, such as better medical treatments, clearly outweigh the harm caused to the animals.

Reception

Activist Ingrid Newkirk wrote about Animal Liberation, "It forever changed the conversation about how we treat animals. It made people—myself included—change what they ate, what they wore, and how they saw animals." Other activists, such as Peter Tatchell and Matt Ball, also said the book changed their views about animals.

Philosopher Peter Singer has said he wishes the book had influenced more people. In September 1999, Singer told The New Yorker that the book’s impact was not as strong as he hoped.

The book has also faced criticism about the ideas behind Singer’s theory on animal rights. In 2001, Richard Posner of Slate wrote that Singer’s theory treats the happiness and suffering of all living things as equally important, even if it means giving more value to a healthy pig than to a child with severe intellectual challenges. Singer disagreed with this claim and had a long discussion with Posner.

Martha Nussbaum argued that the capability approach offers a better way to understand justice than Utilitarianism. She said Utilitarianism overlooks how people adapt to their situations, fails to recognize the unique value of each person, misunderstands emotions like grief, and focuses on total happiness rather than protecting basic rights.

Philosopher Roger Scruton criticized Singer’s work, including Animal Liberation, saying it lacks strong philosophical arguments. He claimed Singer’s ideas rely on a form of Utilitarianism that treats the pain and pleasure of all living things as equally important, ignoring traditional ideas about the differences between humans and animals.

Personal background

In his essay "Animal Liberation: A Personal View," Peter Singer explains how his personal experiences influenced the ideas he presents in the book Animal Liberation. Singer became interested after a lunch in 1970 with a friend, Richard Keshen, who did not eat meat. This made Singer curious about Keshen's decision. He then read Ruth Harrison's book Animal Machines and a paper by Roslind Godlovitch. Later, Godlovitch worked on editing a book called Animals, Men and Morals. These works convinced Singer to become a vegetarian and to consider animal suffering as an important philosophical topic.

Animal Liberation Now

An updated version of the book, titled Animal Liberation Now: The Definitive Classic Renewed, was published on May 23, 2023. This edition includes a new introduction by Yuval Noah Harari. Two-thirds of the book is completely new content. It also describes changes in animal welfare since the original book was published, as well as other developments, such as how eating meat affects the environment and increases the risk of spreading dangerous new viruses.