Formulations 9.3 and 9.4 do not allow the robot to receive any information (other than ) prior to making its decision. Now suppose that the robot has a sensor that it can check just prior to choosing the best action. This sensor provides an observation or measurement that contains information about which nature action might be chosen. In some contexts, the nature action can be imagined as a kind of state that has already been selected. The observation then provides information about this. For example, nature might select the current temperature in Bangkok. An observation could correspond to a thermometer in Bangkok that takes a reading.