• precautionary principle
• anthropocentrism
• principlism

Anthropocentrism—the idea that humans are the most important beings there are—comes in many guises. One version of anthropocentrism states that only humans have full moral status. Those who argue for such a position (beyond merely assuming it) usually refer to some trait that confers moral status and that only humans have. Suggestions include linguistic ability, self-awareness or rationality. However, regardless of what trait one picks it will not track the line between Homo sapiens and other species. You will always be able to find some non-human animal that possesses the trait to a greater degree than some human does— even potentially. Koplin and Wilkinson1 adopt a broadly sentientist position: moral status is conferred by some mental or cognitive function. They discuss two sources of moral uncertainty related to this. In cases of moral uncertainty of the first type, it is uncertain whether Property X confers (full) moral status. In cases of uncertainty of the second type, we assume it to be true that moral status is conferred by X, but it is uncertain whether a particular entity (such as a pig) possesses the property. There are reasons to believe …