Animals/P. Singer: the basis for extending the principle of equality beyond our own species is based on the principle of equal consideration of interests. The strength of this principle lies in the fact that the properties, abilities or disadvantages of others must not lead to their interests being less taken into account.
Animals/Life/P. Singer: When it comes to the question of whether humans should eat animals, an Inuit who would not survive without animal flesh can argue differently than people in mid-latitudes who do not necessarily have to eat meat to survive.
Interest: the principle of equal consideration of interests does not allow higher ranking interests to be infringed for the protection of lower interests (e.g. costs of animal husbandry).
Animal/Person/P. Singer: Can an animal be a person? We can understand "person" here as a being that is rational and self-confident and that experiences itself as separate from other beings, with a past and a future.
Future/consciousness/Animal/P. Singer: both wild and experimental animals have proven that they do indeed have a sense for future situations in which they and their conspecifics have the choice between different options for action. (cf. J. Goodall, The Chimpanzees of Gombe, p. 31, F. de Waal, Chimpanzee Politics, (NY, 1983).
We can assume that some animals are persons in this sense. Then we can ask the question here whether it is all right to kill non-human persons.
Death/killing/Animals/P. Singer: there is no objective assessment that can show that it is worse to kill members of one's own species than members of other species. Then it seems to be worse to kill a chimpanzee than a severely restricted human being who will never be able to be a person (in the above sense). However, this only applies ceteris paribus, i.e. if other factors such as the parents' attitudes are not taken into account.
Person/Animal/Gary Varner/P. Singer: (G. Varner, Personhood and Animals in the Two-Level Utilitarianism of R. M. Hare): according to Varner, a person is a being who has a biographical sense of himself, i.e. who typically can tell a story about himself. According to Varner, animals are close to humans, but have no biographical sense.
Animal/Death/Person/Roger Cruton: (R. Scruton: The Concscientious Carnivore in Food for Thought (Ed. St. Sapontzis (Amherst, NY, 2004) p. 81-91): Thesis: The death of a human being is more a tragedy than the death of an animal,...
...since it is likely that the human being still had plans which he/she wanted to realize, in contrast to an animal which does not have such plans._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
Practical Ethics (Third Edition) Cambridge 2011
The Most Good You Can Do: How Effective Altruism is Changing Ideas About Living Ethically. New Haven 2015