Moore then sketches the evolutionary development of society-highlighting people such as Copernicus, Galileo and Darwin who have made significant contributions to human progress-and making a case for socialism and the women's movement. Moore also criticises the claim that humans are required to kill other animals to prevent overpopulation, as well as the use of the survival of the fittest and an appeal to nature as objections against the New Ethics. He then looks at the question of what humans should eat, exploring the nutrients that humans require and examining human physiology, determining that humans are naturally herbivores he concludes that the ideal diet is vegetarian.
He argues that current developments will lead to a future where humans no longer clothe themselves in animal-based clothing. Moore then criticizes the use of animal products, such as fur, for human clothing and describes alternative methods for humans to clothe themselves using plant-based materials. Moore contends that the ideal relationship would be one were humans and other animals work together for their mutual benefit. He then argues that non-human animals have made, and continue to make, significant contributions to the development of human civilization and that humans treat these beings as mere means to an end. Moore then criticizes what he considers to be the most common objection to the New Ethics thesis: that it is necessary for humans to exploit others to provide for their needs and desires he argues that the objection is egotistical because it fails to consider the perspective of the victims. He laments how humans have become masters over the earth, but have not recognized their responsibilities towards their fellow beings, instead becoming butchers by harming the beings they have duties towards, such as through vivisection, hunting and slaughtering them for food.
Moore then explores human attitudes towards others, looking at both their treatment of other humans and other animals. 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. Moore asserts that the Golden Rule, which he calls "The Great Law", is applicable to all beings, regardless of their species membership. He then lays out his thesis of the New Ethics, arguing that humans are simply individual sentient beings, existing alongside a number of other sentient beings, differing only in degree, not in kind. Moore starts by examining how many new ideas are attacked and ridiculed before they eventually find acceptance in society.