Although I will be defending a hierarchical approach to animal ethics, I do so with considerable misgivings, for I am afraid that some may come away thinking that my aim is to defend an approach that would justify much or all of our current treatment of animals. […] [N]othing like this is remotely the case. Our treatment of animals is a moral horror of unspeakable proportions, staggering the imagination. Absolutely nothing that I say here is intended to offer any sort of justification for the myriad appalling and utterly unacceptable ways in which we mistreat, abuse, and torture animals. […] [I]t seems to me to be true both that animals count for less than people and yet, for all that, that they still count sufficiently that there is simply no justification whatsoever for anything close to current practices.
Shelly Kagan, How to Count Animals, More or Less, Oxford, 2019, pp. 4–5
Suffering, by its nature, is awful, and so one needs an excellent reason to cause it. Occasionally, one will have such a reason. Surgery may cause a human being severe postoperatory pain, but the surgeon may be right to operate if that’s the only way to save the patient.
And what if the sufferer is not a human, but an animal? This doesn’t matter. The underlying principle is that suffering is bad because of what it’s like for the sufferer. Whether the sufferer is a person or a pig or a chicken is irrelevant, just as it’s irrelevant whether the sufferer is white or black or brown. The question is merely how awful the suffering is to the individual.
Stuart Rachels, ‘Vegetarianism’, in T. L. Beauchamp & R. G. Frey (eds.), The Oxford Handbook of Animal Ethics, Oxford, 2012, pp. 883-884
Some writers indeed are so much impressed with the amount of suffering in the world, that they doubt, if we look to all sentient beings, whether there is more of misery or of happiness; whether the world as a whole is a good or bad one. According to my judgment happiness decidedly prevails, though this would be very difficult to prove. If the truth of this conclusion be granted, it harmonizes well with the effects which we might expect from natural selection. If all the individuals of any species were habitually to suffer to an extreme degree, they would neglect to propagate their kind; but we have no reason to believe that this has ever, or at least often occurred. Some other considerations, moreover, lead to the belief that all sentient beings have been formed so as to enjoy, as a general rule, happiness.
Charles Darwin, The Autobiography of Charles Darwin 1809-1882: with the Original Omissions Restored, London, 1958, p. 88
It seems to me that many theories of the universe may be dismissed at once, not as too good, but as too cosy, to be true. One feels sure that they could have arisen only among people living a peculiarly sheltered life at a peculiarly favourable period of the world’s history. No theory need be seriously considered unless it recognises that the world has always been for most men and all animals other than domestic pets a scene of desperate struggle in which great evils are suffered and inflicted. No theory need be seriously considered unless it recognises how utterly alien most of the non-human life even on this small planet is to man and his ideals; how slight a proportion ostensibly living matter bears to the matter which is ostensibly inanimate; and that man himself can live and thrive only by killing and eating other living beings, animal or vegetable. Any optimism which is not merely silly and childish must maintain itself, if it can, in spite of and in conscious recognition of these facts.
C. D. Broad, Examination of McTaggart’s Philosophy, Cambridge, 1938, vol. 2, p. 774
[T]here is something odd about maintaining that pain and suffering are morally significant when felt by a human but not when felt by an animal. If a child burns a hamster alive, it seems quite incredibile to maintain that what is wrong with this act has nothing essentially to do with the pain and usffering the hamster feels. To maintain that the act was wrong because it might encourage the chid to burn other children or encourage anti-social behaviour, because the act failed to exhibit this or that virtue or violated some duty to be kind to animals—to hold these views seems almost perverse, if they are taken to imply that the hamster’s pain and suffering are no central data bearing upon the morality of what was done to it. For us, pain and suffering are moral-bearing characteristics, so that, whether one burns the child or the child burns the hamster, the moralità of what is done is determined at least in part by the pain and suffering the creature in question undergoes. Singer’s utilitarianism picks this feature up quite nicely, and it seems to me exactly right. Of course, there may be other moral-beraing characteristics that apply in the case, but the fact in no way enables us to ignore, morally, the hamster’s pains.
R. G. Frey, ‘Animals’, in Hugh LaFollette (ed.), The Oxford Handbook of Practical Ethics, Oxford, 2003, p. 170
Many believers in animal rights and the relevance of animal welfare do not critically examine their basic assumptions […]. Typically these individuals hold two conflicting views. The first view is that animal welfare counts, and that people should treat animals as decently as possible. The second view is a presumption of human non0interference with nature, as much as possible. […] [T]he two views are less compatible than is commonly supposed. If we care about the welfare and rights of individual animals, we may be led to interfere with nature whenever the costs of doing so are sufficiently low.
Tyler Cowen, ‘Policing Nature’, Environmental Ethics, vol. 25, no. 2 (Summer, 2003)
Humans—who enslave, castrate, experiment on, and fillet other animals—have had an understandable penchant for pretending that animals do not feel pain. On whether we should grant some modicum of rights to other animals, the philosopher Jeremy Bentham stressed that the question was not how smart they are, but how much torment they can feel. […] From all criteria available to us—the recognizable agony in the cries of wounded animals, for example, including those who usually utter hardly a sound—this question seems moot. The limbic system in the human brain, known to be responsible for much of the richness of our emotional life, is prominent throughout the mammals. The same drugs that alleviate suffering in humans mitigate the cries and other signs of pain in many other animals. It is unseemly of us, who often behave so unfeelingly toward other animals, to contend that only humans can suffer.
Carl Sagan & Ann Druyan, Shadows of Forgotten Ancestors, New York, 1992, pp. 371-372
If animals are conscious, then they feel things—for example, pain, fear and hunger—which is intrinsically bad to feel. To inflict deliberately such experiences on an animal for no reason is either to treat the animal as a thing or else in some way to relish its suffering. And surely both those attitudes are immoral.
Roger Scruton, Animal Rights and Wrongs, 2nd ed., London, 1998, p. 21
[O]ther things being equal it is worse to cause an animal pain than to cause an adult human being pain. An adult human being can, as it were, think his or her way around the pain to what lies beyond it in the future; an animal -like a human baby-cannot do this, so that there is nothing for the animal but the pain itself.
Judith Jarvis Thomson, The Realm of Rights, Cambridge, Massachusetts, 1990, pp. 292-293
Human beings are not the only creatures smart enough to suffer[.]
Daniel Dennett, Consciousness Explained, Boston, 1991, p. 449