Normativity in Chimpanzees’ Tool Behavior

In this paper, I will argue that chimpanzees deploy some normative sensitivity when they select (i) materials they will use to manufacture tools and (ii) objects to be used as tools. To defend this claim, I will examine some empirical evidence showing chimpanzees’ remarkable abilities to select adequate tools and materials for the task at hand, as well as reports on how they acquired these abilities, both in their infancy and as naive adults. Based on this evidence, I will argue that these selection processes are guided by evaluations that chimpanzees make about which materials or objects have the required properties to make them efficient tools for a specific task. This turns them into reason-based actions, at least in a modest sense. Furthermore, I will suggest that, after putting together these evaluations and their goals, chimpanzees arrive at “instrumental ought-thoughts” describing an ideal non-actual situation (the possession of a specific tool or material) and prescribing an action (that one chooses that tool or material). These ought-thoughts motivate chimpanzees’ selection behavior. Finally, I will give reasons to prefer the attribution of ought-thoughts to explain chimpanzees’ selection of tools and tool-making material over explanations that only invoke non-normative motivational states.