 As the reader might guess, adding a temporal dimension is typically a good idea, as in most cases it enriches the initial system by allowing us to talk about how the concept changes. Besides epistemic settings, others that benefit from this are systems of  deontic logic,  which study the properties of concepts as permissions (e.g., “\(\varphi\) is allowed”) and obligations (e.g., “\(\varphi\) is required”). Such systems are extremely useful, as they involve topics such as law, social and business organizations, and even security systems.