Animal rights
Animal rights, also known as animal liberation, is the idea that the most basic interests of non-human animals should be afforded the same consideration as the similar interests of human beings. Advocates approach the issue from different philosophical positions, ranging from the protectionist
Animal protectionism
Animal protectionism is a position within the animal rights movement that favors incremental change in pursuit of non-human animal interests. It is contrasted with abolitionism, the position that human beings have no moral right to use animals, and ought to have no legal right, no matter how the...

 side of the movement, presented by philosopher Peter Singer
Peter Singer
Peter Albert David Singer is an Australian philosopher who is the Ira W. DeCamp Professor of Bioethics at Princeton University and Laureate Professor at the Centre for Applied Philosophy and Public Ethics at the University of Melbourne...

—with a utilitarian
Utilitarianism is an ethical theory holding that the proper course of action is the one that maximizes the overall "happiness", by whatever means necessary. It is thus a form of consequentialism, meaning that the moral worth of an action is determined only by its resulting outcome, and that one can...

 focus on suffering and consequences, rather than on the concept of rights—to the abolitionist
Abolitionism (animal rights)
Abolitionism within the animal rights movement is the idea that focusing on animal welfare reform not only fails to challenge animal suffering, but may prolong it by making the exercise of property rights over animals appear acceptable. The abolitionists' objective is to secure a moral and legal...

 side, represented by law professor Gary Francione, who argues that animals need only one right: the right not to be property.

The question is not can they reason, nor can they talk, but can they suffer?

Jeremy Bentham

It is my view that the vegetarian manner of living by its purely physical effect on the human temperament would most beneficially influence the lot of mankind.

Albert Einstein (Letter to Vegetarian Watch-Tower, 27 December 1930)

You have just dined, and however scrupulously the slaughter-house is concealed in the graceful distance of miles, there is complicity, expensive races, — race living at the expense of race.

Ralph Waldo Emerson in "Fate"

The greatness of a nation and its moral progress can be judged by the way its animals are treated.

Mahatma Gandhi

We have enslaved the rest of the animal creation, and have treated our distant cousins in fur and feathers so badly that beyond doubt, if they were able to formulate a religion, they would depict the Devil in human form.

William Ralph Inge

As often as Herman had witnessed the slaughter of animals and fish, he always had the same thought: in their behaviour toward creatures, all men were Nazis. The smugness with which man could do with other species as he pleased exemplified the most extreme racist theories, the principle that might is right.

Isaac Bashevis Singer

A man can live and be healthy without killing animals for food; therefore, if he eats meat, he participates in taking animal life merely for the sake of his appetite. And to act so is immoral.

Leo Tolstoy (On Civil Disobedience)