1. A rule-based data processing apparatus comprising: a processor coupled with first and second memory means, said first memory means having stored therein first and second groups of agents, each group of agents being defined by respective sets of rules, said processor being arranged to run said respective sets of rules in parallel, and said second memory means having stored therein data defining a plurality of objects, at least some of the data having a respective qualifier term associated therewith, the agents of the first group being script agents and being arranged as a sequentially enabled chain, one or more of said script agents including a respective reference to one of said objects and a specified qualifier term; and each of the agents of the second group being object agents and being operable to identify an object and specified qualifier term from a script agent, to identify an instance or each instance of said object in the second memory means, to compare the specified qualifier term with the respective associated qualifier term of each identified object and, when a match occurs, to generate an identifying pointer for the identified and matched object.