The many meanings of "cost" and "benefit" : biological altruism, biological agency, and the identification of social behaviors

The puzzle of how altruism can evolve has been at the center of recent debates over Hamilton’s Rule, inclusive fitness, and kin-selection. In this paper, I use recent debates over altruism and Hamilton’s legacy as an example to illustrate a more general problem in evolutionary theory that has philosophical significance; I attempt to explain this significance and to draw a variety of conclusions about it. The problem is that specific behaviours and general concepts of organism agency and intentionality are defined in terms of concepts of evolutionary “costs” and “benefits,” and these terms have determined the role that agency should play in evolutionary explanation. However, costs, benefits, and agency are not only or even best conceived through evolutionary effects in a biological context. The paper proceeds as follows: first, I explain how the issue of agency relates to the evolutionary puzzle of altruism. Next, I discuss how questions about agency have figured in recent debates over Hamilton’s legacy. In the final section, I argue that Denis Walsh’s “situated Darwinism,” which attempts to return the organism to central status in biological explanation, offers a more productive route for thinking about different forms of costs, benefits, and agency. Finally, I argue that the upshot of all this is that there may be many different, and equally valid, ways to express what organisms are doing and how they are behaving based on different currencies of cost and benefit—even if these may stand in some tension. I illustrate this through returning to the case of altruism and using examples to show that even in non-humans there can be many forms of altruism, even if they are not all biological altruism as defined in the conventional evolutionary terms