Animal welfare regulations require that pain killers be administered to experimental animals subjected to painful experimental procedures even if the animal is subsequently killed. From the point of the animal, is there any utility in this requirement? Assume that there is no utility if the animal is killed immediately after the pain since it will no longer have a memory of the pain when it is dead. Then, it would seem the regulations are misguided (if their intent is only to protect the animal) and it would be ethical to not administer a pain killer. With this assumption, is there some interval in which it would become unethical? If it is concluded that it is impossible to define an interval since for every interval the animal would no longer have a memory of the pain at the end of the interval when it is dead. If this is the case, then would it always be ethically acceptable not to administer pain killers, since all animals will die eventually.

You seem to be assuming that the only bad thing about pain is that it will be remembered. But is this right? I think not. One way to argue against the assumption is by analogy: if the assumption were correct, then presumably the only bad thing about memories of pain would be that they will be remembered. And so on up. So long as all sentient beings die eventually, there would then be nothing bad (or good?) about their experiences because all memory of them would eventually disappear. Rejecting what you assume, we would say that pain itself is also distressing and therefore bad. In fact, without that distress of pain itself it's hard to understand why memories of pain should be distressing. If pain itself is distressing and bad, then it makes sense to avoid and alleviate pain. And this is in fact what we routinely do when we offer palliative care to a patient who would otherwise die in great pain. The case of the animals you describe is essentially similar. Just as it is less bad if the...