Animal rights took center stage last night as Peter Singer delivered a talk titled “All Animals Are Equal, But in What Sense?” to a full house in Dinkelspiel Auditorium.

Singer, a professor of bioethics at Princeton University, was the final speaker in “The Ethics of Food & the Environment” series, organized by the Barbara and Bowen McCoy Program in Ethics in Society over winter and spring quarter.

“I think choices about what we eat is a really important topic,” Singer said, explaining that he would be addressing the issue from an ethical viewpoint.

Singer is often credited with initiating the animal rights movement with the publication of his book “Animal Liberation” in 1975 — the first chapter is titled “All Animals Are Equal.”

“I stand by this view but it has been misrepresented,” Singer said. “We need to clarify what we mean.”

Singer began his talk by outlining past and current views of the people’s relationship with animals. Of the few past philosophers who address this issue — among them Aristotle and Kant — there is a dominant view that animals simply do not count as living beings deserving of ethical treatment.

“We have a background that would license us to do anything to animals that furthered what we wanted to do,” Singer said.

He went on to explain that by “animals,” he does not mean every creature that is zoologically classified as an animal, but only animals with consciousness. Singer thinks evidence for consciousness can be found in anatomical similarities to humans and in our similar behaviors, especially to painful situations like being burned. He believes this consciousness is most clear for vertebrates but will not rule it out as a possibility for other animals.

Singer described the mainstream view toward animals today as a combination of kindness and cruelty.

“If you ask people today, most would say that animals do matter and that we have a duty not to be cruel to them,” he said. “They would say that animals do have interests but that they are overridden by human interests, which include getting animal products — like meat and eggs — cheaply.”

Singer defended the view of equality among all creatures: he has an objection to “speciesism” and drew an analogy to racism.

“In both cases, we have a dominant group who doesn’t think that they have to confer the same weight on the interests of the other groups,” Singer said. “The most extreme form of racism, slavery, is the closest to our view of animals.”

He went on to explain that animals are sentient beings with interests, especially the interest of being prevented from feeling pain.

“Pain is pain, no matter the being who is feeling it,” Singer said. “We shouldn’t give less weight to [animals’] interest to not feel pain just because of their species.”

He further explained how the issue of animal pain translates into an ethical issue.

“I’m not saying all beings feel pain in the same way,” he said. “There are all sorts of differences, which I don’t deny, in the nature of beings, but this is a moral equality.”

Singer’s argument of the equal consideration of interests, which requires us to give equal weight to similar interests, irrespective of species, has implications for eating meat from farmed animals, the source of most meat consumed in the United States. Over 10 billion vertebrates are killed annually in food production in the U.S.

Singer described some of the practices in the production of meat and animal products — including battery-caged hens for egg production and sow stalls for pork — explaining that equal consideration of interests finds the suffering these practices inflict on animals indefensible.

Though Singer argued that pain is bad for all species, he did not argue that premature death is a similar loss for all species. Instead, he explained that premature death is a greater or lesser loss, depending on factors such as a being’s awareness of its existence over time and its ability to plan for the future.

Though he is a vegan and has been a vegetarian since 1971, Singer does not condemn all meat eating absolutely. He presented Rodger Scruton’s view of “Conscientious Omnivorism,” similar to the ideas of Michael Pollan, and noted that eating meat could be justified in some cases.

“You could argue that people give animals a good life and existence if they raise them for meat,” Singer said. “This could be a justification for eating meat and animal products if people are very conscious about where they’re getting their meat from.”

Citing the example of free-range hens on an organic farm in New Jersey, Singer said, “It is hard to say it would be wrong to eat eggs from this type of operation, but genuinely free-range eggs is a hard commodity to come by in the U.S.”

“It becomes difficult to be a conscious omnivore,” he added, “and is often simpler, clearer and sends a better message to not eat animals or animal products at all.”