Speciesism is a term used in philosophy regarding the treatment of individuals of different species. The term has several different definitions. Some specifically define speciesism as discrimination or unjustified treatment based on an individual's species membership, while others define it as differential treatment without regard to whether the treatment is justified or not. Richard D. Ryder, who coined the term, defined it as "a prejudice or attitude of bias in favour of the interests of members of one's own species and against those of members of other species". Speciesism results in the belief that humans have the right to use non-human animals in exploitative ways which is pervasive in the modern society. Studies from 2015 and 2019 suggest that people who support animal exploitation also tend to have intersectional bias that encapsulates and endorses racist, sexist, and other prejudicial views, which furthers the beliefs in human supremacy and group dominance to justify systems of inequality and oppression.
Great ape personhood is a movement to extend personhood and some legal protections to the non-human members of the great ape family: bonobos, chimpanzees, gorillas, and orangutans.
A person is a being who has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts.
Gary Lawrence Francione is an American academic in the fields of law and philosophy. He is Board of Governors Professor of Law and Katzenbach Scholar of Law and Philosophy at Rutgers University in New Jersey. He is also a visiting professor of philosophy at the University of Lincoln (UK) and honorary professor of philosophy at the University of East Anglia (UK). He is the author of numerous books and articles on animal ethics.
Steven M. Wise was an American lawyer and legal scholar who specialized in animal rights, primatology, and animal intelligence. He taught animal rights law at Harvard Law School, Vermont Law School, John Marshall Law School, Lewis & Clark Law School, Tufts University School of Veterinary Medicine, and at the Master’s in Animal Law and Society of the Autonomous University of Barcelona. He was a former president of the Animal Legal Defense Fund and founder and president of the Nonhuman Rights Project. The Yale Law Journal had called him "one of the pistons of the animal rights movement."
Animal law is a combination of statutory and case law in which the nature – legal, social or biological – of nonhuman animals is an important factor. Animal law encompasses companion animals, wildlife, animals used in entertainment and animals raised for food and research. The emerging field of animal law is often analogized to the environmental law movement because "animal law faces many of the same legal and strategic challenges that environmental law faced in seeking to establish a more secure foothold in the United States and abroad".
Animal rights is the philosophy according to which many or all sentient animals have moral worth independent of their utility to humans, and that their most basic interests—such as avoiding suffering—should be afforded the same consideration as similar interests of human beings. The argument from marginal cases is often used to reach this conclusion. This argument holds that if marginal human beings such as infants, senile people, and the cognitively disabled are granted moral status and negative rights, then nonhuman animals must be granted the same moral consideration, since animals do not lack any known morally relevant characteristic that marginal-case humans have.
The Case for Animal Rights is a 1983 book by the American philosopher Tom Regan, in which the author argues that at least some kinds of non-human animals have moral rights because they are the "subjects-of-a-life", and that these rights adhere to them whether or not they are recognized. The work is considered an important text within animal rights theory.
Plant rights are rights to which certain plants may be entitled. Such issues are often raised in connection with discussions about human rights, animal rights, biocentrism, or sentientism.
Personhood is the status of being a person. Defining personhood is a controversial topic in philosophy and law and is closely tied with legal and political concepts of citizenship, equality, and liberty. According to law, only a legal person has rights, protections, privileges, responsibilities, and legal liability.
Steven Frederic Sapontzis is an American moral philosopher. He is professor emeritus of philosophy at California State University, East Bay and specializes in animal ethics, environmental ethics and meta-ethics. His best known work is Morals, Reason, and Animals, published in 1987. Sapontzis' philosophy advocates for extending moral personhood and ethical consideration to animals based on their capacity for interests and suffering, challenging anthropocentric norms and speciesism, and instead promoting empathy, vegan activism, and systemic change to reduce animal exploitation.
An Introduction to Animals and Political Theory is a 2010 textbook by the British political theorist Alasdair Cochrane. It is the first book in the publisher Palgrave Macmillan's Animal Ethics Series, edited by Andrew Linzey and Priscilla Cohn. Cochrane's book examines five schools of political theory—utilitarianism, liberalism, communitarianism, Marxism and feminism—and their respective relationships with questions concerning animal rights and the political status of (non-human) animals. Cochrane concludes that each tradition has something to offer to these issues, but ultimately presents his own account of interest-based animal rights as preferable to any. His account, though drawing from all examined traditions, builds primarily upon liberalism and utilitarianism.
Animal Rights Without Liberation: Applied Ethics and Human Obligations is a 2012 book by the British political theorist Alasdair Cochrane, in which it is argued that animal rights philosophy can be decoupled from animal liberation philosophy by the adoption of the interest-based rights approach. Cochrane, arguing that there is no reason that (nonhuman) animals should be excluded from justice, adopts Joseph Raz's account of interest rights and extends it to include animals. He argues that sentient animals possess a right not to be made to suffer and a right not to be killed, but not a right to freedom. The book's chapters apply Cochrane's account to a number of interactions between humans and animals; first animal experimentation, then animal agriculture, the genetic engineering of animals, the use of animals in entertainment and sport, the relationship of animals to environmental practices and the use of animals in cultural practices.
John Hadley is an Australian philosopher whose research concerns moral and political philosophy, including animal ethics, environmental ethics, and metaethics. He is currently a senior lecturer in philosophy in the School of Humanities and Communication Arts at Western Sydney University. He has previously taught at Charles Sturt University and the University of Sydney, where he studied as an undergraduate and doctoral candidate. In addition to a variety of articles in peer-reviewed journals and edited collections, he is the author of the 2015 monograph Animal Property Rights and the 2019 monograph Animal Neopragmatism. He is also the co-editor, with Elisa Aaltola, of the 2015 collection Animal Ethics and Philosophy.
Political Animals and Animal Politics is a 2014 edited collection published by Palgrave Macmillan and edited by the green political theorists Marcel Wissenburg and David Schlosberg. The work addresses the emergence of academic animal ethics informed by political philosophy as opposed to moral philosophy. It was the first edited collection to be published on the topic, and the first book-length attempt to explore the breadth and boundaries of the literature. As well as a substantial introduction by the editors, it features ten sole-authored chapters split over three parts, respectively concerning institutional change for animals, the relationship between animal ethics and ecologism, and real-world laws made for the benefit of animals. The book's contributors were Wissenburg, Schlosberg, Manuel Arias-Maldonado, Chad Flanders, Christie Smith, Clemens Driessen, Simon Otjes, Kurtis Boyer, Per-Anders Svärd, and Mihnea Tanasescu. The focus of their individual chapters varies, but recurring features include discussions of human exceptionalism, exploration of ways that animal issues are or could be present in political discourse, and reflections on the relationship between theory and practice in politics.
Gary Edward Varner was an American philosopher specializing in environmental ethics, philosophical questions related to animal rights and animal welfare, and R. M. Hare's two-level utilitarianism. At the time of his death, he was an emeritus professor in the department of philosophy at Texas A&M University; he had been based at the university since 1990. He was educated at Arizona State University, the University of Georgia, and the University of Wisconsin–Madison; at Madison, where he was supervised by Jon Morline, he wrote one of the first doctoral theses on environmental ethics. Varner's first monograph was In Nature's Interests?, which was published by Oxford University Press in 1998. In the book, Varner defended a form of biocentric individualism, according to which all living entities have morally considerable interests.
Sentientist Politics: A Theory of Global Inter-Species Justice is a 2018 book by the English political theorist Alasdair Cochrane, published by Oxford University Press. In the book, Cochrane outlines and defends his political theory of "sentientist cosmopolitan democracy". The approach is sentientist in that it recognises all sentient animals as bearers of rights; cosmopolitan in that it extends cosmopolitan political theory to include animals, rejecting the importance of state borders and endorsing impartiality; and democratic in that it aims to include animals in systems of representative and cosmopolitan democracy. It was the first book to extend cosmopolitan theory to animals, and was a contribution to the "political turn" in animal ethics – animal ethics informed by political philosophy.
Moral Inquiries on the Situation of Man and of Brutes is an 1824 book by Lewis Gompertz, an early animal rights advocate and vegan. The book argues that animals, like humans, are sentient beings capable of experiencing pain and pleasure, and thus deserve moral consideration. He critiques the exploitation of animals for labour, food, and clothing, condemning practices such as slaughter, hunting, and scientific experimentation. He also addresses the suffering of wild animals, suggesting that even in nature, animals face hardships such as hunger and predation.
Evolutional Ethics and Animal Psychology is an 1897 book by the American scholar and early animal rights advocate Edward Payson Evans. It is an in-depth exploration of the intersection between ethical theory and animal psychology, with a particular focus on the rights of animals and the moral obligations humans have toward them.
The Moral Circle: Who Matters, What Matters, and Why is a 2025 book by philosopher Jeff Sebo. In the book, Sebo calls for a fundamental shift in ethics, advocating for the expansion of humanity's moral circle to include not just humans, but also animals, insects, AI systems, and even microbes. He critiques human exceptionalism, emphasizing how human current treatment of nonhumans—whether through factory farming, captivity, or technological development—often neglects their interests. Through case studies on captive elephants, farmed insects, and the ethical dilemmas of creating digital minds, Sebo explores how expanding the moral circle could transform society. As humanity continues to reshape the world, he argues for a rethinking of human ethical responsibilities and the implementation of systemic changes to create a more just and inclusive future.
