Biological Life and the Partiality Relation

Abstract

The first chapter defends an account of the metaphysics of identity which combines two sensible claims in the personal identity literature. The first is a Parfitian thesis that we are persons whose persistence is tied to the appropriate continuity of certain psychological activities. The second is an Animalist thesis that we are human animals whose persistence is tied to the continuation of biological functioning such as respiration and metabolism. Supporters of the former often argue against the latter and vice versa. I argue that both are true on the grounds that there is good reason to believe that psychological activities of the human animal count as forms of biological functioning. I then motivate the substantive thesis that we are neither human animals nor persons essentially. What we are essentially is a broader thing—an organism—which can be a human animal, person, or both, but need not be either of them.

The second chapter considers diachronic questions about when an organism at one moment persists at the next. I claim that the persistence of a kind of event—a biological life—is a crucial piece of the persistence of an organism, and that the appropriate continuation of biological activities is necessary and sufficient for the persistence of biological life. I offer a performance-centered account of “appropriate biological functioning” which can be applied to biological activities ranging from digesting, breathing, perceiving, and feeling. It depends on two forms of “functional continuity”. The first, intra-functional continuity, consists in chains of causal dependence between token instances of the same function-type. The second, inter-functional continuity, consists of chains of causal dependence between token instances of distinct function-types. I suggest that organisms are best conceived as systems consisting of a set of distinct biological activities which are connected to one another by both the intra-functional continuity and inter-functional continuity relation.

In the third chapter, I argue for the thesis that one significant source of the relation of partiality comes from degrees of biological connectedness and continuity between organisms. I argue that this account fares better than a competing account of the source of partiality which relies on psychological connectedness and continuity. I then answer a skeptical challenge about why biological connections and continuity generate the relation of partiality. Although I am not an egoist, I end the chapter by suggesting that my position may make egoism more tolerable than it would be otherwise.