Peter Singer is a utilitarian thinker. He feels that morality depends on how we provide utility, pleasure or happiness to human beings. In contrast, Tom Regan's view is absolutist. He believes that all living creatures are equal because they all have certain cognitive and experiential abilities. In short, Peter thinks that animals should be used for human pleasure or happiness. Tom opposes this idea and suggests that animals have equal rights and should not be used for the pleasure and happiness of human beings.