How did Peter Singer revive philosophical debates about vegetarianism and animal rights?

Peter Singer revived philosophical debates about vegetarianism and animal rights primarily through his influential 1975 book, Animal Liberation: A New Ethics for Our Treatment of Animals.12

His approach was grounded in utilitarianism, which evaluates the morality of actions based on their ability to promote happiness or prevent pain. Singer’s key contributions included:1

• Challenging Speciesism: He popularized the concept of "speciesism," arguing that species membership is not a morally relevant criterion for determining how a being should be treated. He contended that all beings capable of suffering or enjoyment possess interests that must be considered in moral decision-making.1
• Critiquing Factory Farming: By highlighting the routine abuse of animals in intensive animal farming and scientific research, he argued that such practices are morally unjustified.3
• Establishing Applied Ethics: His work moved animal rights from the periphery into the mainstream of applied ethics, prompting philosophers to rigorously examine whether traditional human treatment of animals is defensible.12

Singer’s work fundamentally shifted the discourse, asserting that the capacity for suffering, rather than human-centric traits, should dictate our moral obligations to other sentient creatures.1