This paper elaborates and defends a familiar ‘transparent’ account of knowledge of one's own beliefs, inspired by some remarks of Gareth Evans, and makes a case that the account can be extended to mental states in general, in particular to knowledge of one's intentions.

What is required for several agents to intentionally φ together? I argue that each of them must believe or assume that their φ-ing is a single end that each intends to contribute to. Various analogies between intentional singular action and intentional joint action show that this doxastic single end condition captures a feature at the very heart of the phenomenon of intentional joint action. For instance, just as several simple actions are only unified into a complex intentional singular activity if (...) the agent believes or assumes that there is a single end that each action is directed to, so several agents’ actions are only unified into an intentional joint activity if each agent believes or assumes that there is a single end that each intends to contribute to. Influential accounts of intentional joint action, including Christopher Kutz’s and Michael Bratman’s, implicitly include this condition only if participants must intend to contribute to the end under the same conception. While such a requirement successfully rules out some counterexamples, it also makes the accounts unable to appropriately accommodate and explain clear cases of intentional joint action that they ought to be able to accommodate and explain. (shrink)

Most reductionist accounts of intentional joint action include a condition that it must be common knowledge between participants that they have certain intentions and beliefs that cause and coordinate the joint action. However, this condition has typically simply been taken for granted rather than argued for. The condition is not necessary for ensuring that participants are jointly responsible for the action in which each participates, nor for ensuring that each treats the others as partners rather than as social tools. It (...) is thus something of a mystery why the condition is so widely accepted. By rejecting three arguments that could potentially support it, I argue that reductionists should get rid of the condition. I show that two of the arguments fail. While the third argument is intuitively compelling, it builds on key premises that are unavailable to the reductionist. (shrink)