An endless loop in an inference engine processing a set of rules according to facts stored in a database may be detected by: (a) analyzing the set of rules to identify a subset of the set of rules comprising rules that are triggered by an updated fact; (b) executing the rules of the subset; (c) updating at least one of the facts based on the execution of the rules; (d) storing an identifier for each executed rule of the subset; (e) associating each stored identifier with a subset number for the subset in a consecutive sequence of subset numbers for executed subsets; and repeating steps (a)-(e) until the identifier for a rule, to be executed, is associated with an excessive number of subset numbers that are equally offset from each other in the sequence of subset numbers for executed subsets.