the assignment of value to individuals based on (animal) species membership alone. Divisions within animal rights theory include the utilitarian, protectionist approach, which pursues improved conditions for animals. It also pertains to the rights-based abolitionism, which seeks to end human ownership of non-humans, including as pets. Abolitionists argue that protectionism serves only to make the public feel that animal use can be morally unproblematic (the "happy meat" position). Donald Watson, co-founder of The Vegan Society, stated in response to a question on why he was an ethical vegan, "If an open-minded, honest person pursues a course long enough, and listens to all the criticisms, and in one's own mind can satisfactorily meet all the criticisms against that idea, sooner or later one's resistance against what one sees as evil tradition has to be discarded." On bloodsports, he has said that "to kill creatures for fun must be the very dregs," and that vivisection and animal experimentation "is probably the cruelest of all Man's attack on the rest of Creation." He has also stated that "vegetarianism, whilst being a necessary stepping-stone, between meat eating and veganism, is only a stepping stone." Alex Hershaft, co-founder of the Farm Animal Rights Movement and Holocaust survivor, states he "was always bothered by the idea of hitting a beautiful, living, innocent animal over the head, cutting him up into pieces, then shoving the pieces into [his] mouth," and that his experiences in the Nazi Holocaust allowed him "to empathize with the conditions of animals in factory farms, auction yards, and slaughterhouses" because he "knows firsthand what it's like to be treated like a worthless object." Several animal rights activists including Isaac Bashevis Singer, Gary Yourofsky and Karen Davis have compared the cruel treatment of animals in CAFOs and slaughterhouses to the Holocaust. Law professor Gary Francione, an abolitionist, argues that all sentient beings should have the right not to be treated as property, and that adopting veganism must be the baseline for anyone who believes that non-humans have intrinsic moral value. Philosopher Tom Regan, also a rights theorist, argues that animals possess value as "subjects-of-a-life", because they have beliefs, desires, memory and the ability to initiate action in pursuit of goals. The right of subjects-of-a-life not to be harmed can be overridden by other moral principles, but Regan argues that pleasure, convenience and the economic interests of farmers are not weighty enough. Philosopher Peter Singer,