When our interests or the interests of those we care for will be hurt, we do not recognize a moral obligation to "let nature take its course," but wh… - Steve F. Sapontzis

Aristotle thought that men were naturally superior to women and Greeks naturally superior to other races; Victorians thought white men had to shoulder the burden of being superior to savages; and Nazis thought Aryans were a master race. We have come to reject these and many other supposedly natural hierarchies; the history of what we consider moral progress can be viewed as, in large part, the replacement of hierarchical worldviews with a presumption in favor of forms of egalitarianism. This substitution places the burden of proof on those who would deny equal consideration to the interests of all concerned, rather than on those who seek such consideration. Consequently, some reason is needed to justify the fairness of maintaining a hierarchical worldview when we are dealing with animals.

When healthy animals, whose prospects include the possibility of lives that are worth living, are killed, then they suffer the loss of those prospects, even if they do not suffer pain or anxiety in the killing process. So, the mass killing or "slaughter" of animals for food always involves mass suffering. If the phrase "humane slaughter" is supposed to indicate a killing process without suffering, it is a false label.

1. We are morally obligated to alleviate unjustified animal suffering that it is in our power to prevent without occasioning as much or more unjustified suffering.
2. Innocent animals suffer when they are preyed upon by other animals.
3. Therefore, we are morally obligated to prevent predation whenever we can do so without occasioning as much or more unjustified suffering than the predation would create, and we are also morally obligated to attempt to expand the number of such cases.