A prominent and respected philosopher of animal rights law and ethical theory, Gary L. Francione is known for his criticism of animal welfare laws and regulations, his abolitionist theory of animal rights, and his promotion of veganism and nonviolence as the baseline principles of the abolitionist movement. Unlike Peter Singer, Francione maintains that we cannot morally justify using animals under any circumstances, and unlike Tom Regan, Francione's theory applies to all sentient beings, not only to those who have more sophisticated cognitive abilities.