Side-effect actions, acting for a reason, and acting intentionally

What is the relation between acting intentionally and acting for a reason? While this question has generated a considerable amount of debate in the philosophy of action, on one point there has been a virtual consensus: actions performed for a reason are necessarily intentional. Recently, this consensus has been challenged by Joshua Knobe and Sean Kelly, who argue against it on the basis of empirical evidence concerning the ways in which ordinary speakers of the English language describe and explain certain side-effect actions. Knobe and Kelly's argument is of interest not only because it challenges a widely accepted philosophical thesis on the basis of experimental evidence, but also because it indirectly raises an important and largely neglected question, the question of whether or in what sense an agent can perform a side-effect action for a reason. In this article, I address this question and provide a positive answer to it. Specifically, I argue that agents act for a reason whenever they perform side-effect actions as trade-offs. Thus, I claim that there are three distinct types of rational action: actions performed as ends in themselves, actions performed as means to further ends, and side-effect actions performed as trade-offs. Given this multiplicity of types of rational action, the question of whether or not actions performed for a reason are necessarily intentional is in need of refinement. The more specific question that lies at the heart of this article is whether or not side-effect actions performed as trade-offs are necessarily intentional. I conclude that, contrary to what Knobe and Kelly suggest, the question remains open