We're just beginning to implement iLog Rules for .Net at work. A common debate is whether we should use a rules engine for validating data. Certainly, one can use a rules engine for validating data but it seems like a misuse of the technology.
In my mind, a business rule is a policy that governs a business action. The data should already be valid before invoking the business rule/policy. Of course, the business rule/policy must handle invalid data, ergo the ambiguity between data validation and business policy.
For example, let's say you have a business policy that determines an action based on...