In his book The New Ethics, American zoologist and philosopher J. Howard Moore argued that humans are simply individual sentient beings, existing alongside a number of other sentient beings, differing only in degree, not in kind.

Moore asserts that the Golden Rule, which he calls "The Great Law", is applicable to all beings, regardless of their species membership.

He contends that the New Ethics is an ethical consequence of Darwin's theory of evolution, which established that all beings are related to each other and that it rejected the anthropocentric belief that non-human animals were produced for the benefit of humans.