Killing invertebrates is an under-explored area in animal welfare and environmental ethics. While some researchers have argued invertebrates are conscious (Elwood and Apel 2009; Merker 2007; Tye 2000; Crook, Hanlon and Walter 2013; Mather 2008; Klein and Barron 2016), have beliefs and desires (Tye 2000; Carruthers 2005), and that the humane treatment principle ought to be extended to invertebrates (Cooper 2011; Crook 2013; see also Fischer 2016), little attention has been paid to the ethics of painless killing. Does a painless death harm an invertebrate? An answer to this question will inform an answer to the related question: when, if ever, is it wrong to painlessly kill an invertebrate? If death does not harm an invertebrate, then it is unlikely that it will ever be directly wrong to painlessly kill it. Judgements about the harm of death involve drawing conclusions about the psychological life of an animal. The psychological capacities of an animal determine whether it ought to be included within the scope of the moral theories that are ordinarily drawn upon to answer questions about the ethics of killing. If death does not harm an invertebrate, then it suggests its psychological life does not warrant that the animal have a place in moral theorizing.
My aim in this paper is to explain a meaningful sense in which death is a misfortune for an invertebrate. The account presented is a logical implication of bringing together two distinct pieces of theory: the deprivation account of the harm of death (Nagel 1979; McMahan 2002: Chap.2; Palmer 2010: 134-137) and the biocentric ethical theory developed by the New Zealand philosopher, Nicholas Agar (2001). Combined, the two theories support the following thesis: death harms an invertebrate because it deprives the individual of future biopreference satisfaction. Counter-intuitively, Agar claims that it does not matter whether the organism cares about the satisfaction of the preferences or can conceive of the future in any way. He says: The teleological approach to preferences reveals the diachronic interconnectedness of an organism’s behavioural projects. The lack of an ability to conceive oneself as existing over time does not prevent an organism from having a wide range of behavioural projects that requires its future existence (124). Because Agar identifies the good for an organism with the pursuit of environment-directed goals – ‘biopreferences’ ― (2001: p. 94), death will be bad for that organism because it forecloses the chance to achieve these goals. As we will see below, for Agar what matters is not whether the organisms are sentient and feel pleasure or pain, but whether their biological goals can be specified in a scientifically credible way to be plausible analogues for the preferences or desires of Homo sapiens and other mammals.