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Goals and backward chaining using the Rete Algorithm

I was prompted to post this by request from Mark Proctor and Peter Lin and in response to recent comments on CEP and backward chaining on Paul Vincent’s blog (with an interesting perspective here).

I hope those interested in artificial intelligence enjoy the following paper .  I wrote it while Chief Scientist of Inference Corporation.  It was published in the International Joint Conference on Artificial Intelligence over twenty years ago. 

The bottom line remains:

  1. intelligence requires logical inference and, more specifically, deduction
  2. deduction is not practical without a means of subgoaling and backward chaining
  3. subgoaling using additional rules to assert goals or other explicit approaches is impractical
  4. backward chaining using a data-driven rules engine requires automatic generation of declarative goals

We implemented this in Inference Corporation’s Automated Reasoning Tool (ART) in 1984.  And we implemented it again at Haley a long time ago in a rules langauge we called “Eclipse” years before Java.

Regretably, to the best of my knowledge, ART is no longer available from Inference spin-off Brightware or its further spin-off, Mindbox.  To the best of my knowledge, no other business rules engine or Rete Algorithm automatically subgoals,  including CLIPS, JESS, TIBCO Business Events (see above), Fair Isaac’s Blaze Advisor, and Ilog Rules/JRules.  After reading the paper, you may understand that the resulting lack of robust logical reasoning capabilities is one of the reasons that business rules has not matured to a robust knowledge management capability, as discussed elsewhere in this blog.  Continue reading “Goals and backward chaining using the Rete Algorithm”

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Haley / ART syntax lives on in open-source Java rules

The ART syntax lives on in yet another product! 

JBOSS Rules (formerly Drools) just described its imminent support for rules expressed in the CLIPS syntax here.

NASA derived CLIPS from the syntax of Inference Corporation’s Automated Reasoning Tool (ART) in the mid-80s.  I designed and implemented the ART syntax with Chuck Williams on a team with Brad Allen and Mark Wright. 

CLIPS didn’t have many of the features of ART (including an ATMS or backward chaining, for example), but it Continue reading “Haley / ART syntax lives on in open-source Java rules”

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Missing Goals and Requirements in Business Rules

Both of the following statements are true, but the first is more informative:

  1. Business Rules Management Systems (BRMS) typically produce forward chaining production rules that are interpreted by[1] a business rules engine (BRE) based on the Rete Algorithm.
  2. BRMS typically generate rules that are interpreted by a BRE.

First, dropping the word “production” before “rules” loses information. BRMS do not typically generate rules that are not production rules. Consider, for example, the BRMS vendors involved in the OMG effort produced the Production Rule Representation (PRR) standard. The obvious question is:

  • What is different about production rules?

Second, dropping the words “based on the Rete Algorithm” loses information. The dominant rules vendors and open-source engines are all based on the Rete Algorithm.

  • Why does the Rete Algorithm matter?

Third, dropping the word “chaining” before “rules” loses information. Chaining refers to the sequential application of rules, as in a chain where each link is the application of one rule and links are tied together by their interaction. But:

  • Why does chaining matter?

Fourth, dropping the word “forward” before “chaining” loses information. Forward chaining reacts to information without requiring goals. This begs the question:

  • Don’t goals matter?

Continue reading “Missing Goals and Requirements in Business Rules”