One of the recurring topics in the rules world is forward chaining vs. backward chaining – how they compare, when to use one or the other, and which implementations even offer back chaining. I suspect that a lot of the confusion around backward chaining is simply due to the fact that most folks haven’t implemented production-quality systems that make use of it.
Backward chaining systems are more limited than forward chaining systems.
Dietrich points out that the article was located on the old Rulespower site and disappeared with the purchase by Fair Isaac.
I’m posting here simply to point out that the Wayback Machine has them.
Charles Forgy on Forward and Backward Chaining
I have linked directly to the latest archived version of each article segment. You can find all the RulesPower content that they have here.
For further reading on the topic, the discussions at the following links are interesting (in no particular order):
- Paul Haley on backward chaining using rete
- Paul Vincent on goal-directed event processing – in which he points out that backward chaining was dropped from PRR due to lack of vendor interest
- James Owen on the problems with performing full opportunistic backward chaining on a forward chaining engine