Abstract

In the last decade, the study of moral heuristics has gained in importance. I argue that we can consider speciesism as a moral heuristic: an intuitive rule of thumb that substitutes a target attribute (that is difficult to detect, e.g. “having rationality”) for a heuristic attribute (that is easier to detect, e.g. “looking like a human being”). This speciesism heuristic misfires when applied to some atypical humans such as the mentally disabled, giving them rights although they lack rationality. But I argue that it is not necessarily irrational or inconsistent to hold on to this heuristic rule, because we have to take time and knowledge constraints, uncertainty aversion and emotional costs into account. However, this “heuristic defense” of speciesism uses a target attribute (rationality) that has implications of disrespect towards some atypical humans. Therefore, based on notions of impartiality and compassion, I argue for a morally better target attribute: sentience (“having a sense of well-being”). “Being a vertebrate” is suitable as a corresponding heuristic attribute because it is easy to detect and has a strong correlation with the target attribute of sentience