Abstract
Forthy years after the issue of Animal Liberation (1975), this essay tries to make a critical assessment of the theses of Peter Singer on the moral status of animals, showing their historical evolution. Notwithstanding the limits of his utilitarian theoretical view, a good part of Singer’s moral reflection about animals reveals itself convincing and is finding some achievements in the positive legislation of a lot of countries. Following David DeGrazia, the author develops Singer’s theses in a gradualist direction, pointing out that the problems of utilitarianism do not compromise the validity of the principle of equal consideration of interests, nor the main practical out-comes that the Australian philosopher draws from it.