We introduce a formal language for multi-agent systems based on new modal operators. The modal operators express concurrency at the syntactic level. Operators containing quantifiers describe the evolution of a system where each agent has knowledge of other agents’ attitude toward a goal but not of their actions. This result is obtained without introducing standard epistemic operators. The semantics presents a mixture of Tarskian and game-theoretical elements. We apply game-theory to interpret the quantified modalities and to determine which information is available to the agents as well as their reasoning capabilities.