Abstract
Most theories of intentional action agree that if acting for a reason is a necessary condition for the action in question to be an intentional action, the reason need not genuinely justify it. The same should hold for shared intentional action, toward which philosophers of action have recently turned their attention. I argue that some of the necessary conditions proposed for shared intention turn out to require that we deny this claim. They entail that shared intention is possible only if the participating agents form their intentions on the grounds of genuinely rational considerations. Thus, they “over-rationalize,” as I call it, shared intention