The invention concerns a device with a supervising unit arranged to handle a rule system for the behavior of an entity. The supervising unit comprises at least one storage member in which a set of rules for the behavior is stored. The device also has a user interface comprising a presenter for presenting information, preferably concerning decisions which are made and/or recommended, to a user. The device is arranged with a first and a second rule handler which can work in parallel with each other. The presenter can simultaneously present information concerning the rule handling which is carried out by the first rule handler and the rule handling which is carried out by the second rule handler. The invention also concerns a use, a system comprising a device according to the invention as well as storage media with computer programs for implementing the invention.