Talk:Backward chaining

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Additional information: Related task forces (core areas): Logic

I changed The example to reflect changes I made to Forward chaining. --CH

1. If Fritz croaks and eats flies - Then Fritz is a frog 2. If Fritz is a frog - Then Fritz is green

The conclusion in the 5th paragraph: Fritz croaks and eats flies, so must be green; Fritz is green, so must be a frog.

This is inconsistent with the rules of inference. Did you mean "Fritz croaks and eats flies, so must be a frog; Fritz is frog, so must be a green"? --DL

This example is just wrong - it is forward, not backward chaining.

Why is the backward chaining example the same as the forward chaining example if they are different?

This article isn't very clear.

134.225.254.250 08:32, 23 April 2007 (UTC)

Some of the Prolog material online contains academic discussion on this topic. Unless someone beats me to it, I'll try to look it up again for stub improvement. Hotfeba 19:00, 28 July 2007 (UTC)

I think it's pretty clear. And the example should be the same because the difference is not in the rules but in the inference algorithm using it. Goal-driven is backward (working from the conclusion back to the antecedent) and data-driven is forward (working from antecedent to conclusion). I only have an issue with the analogy used with "top-down" and "bottom-up" -- IMO data driven is bottom up (because you start with the nitty-gritty detail and end at an abstraction) and goal driven is top-down (begin with abstraction and work your way to the detail.) Think of language parsers as special examples of it: if you work the grammar rules from sentence down to parts and try to match words, you do top-down parsing, goal-driven. If you start with the words finding rules which match the sequence you see, then you do bottom-up parsing, data driven. My other concern is that the rules should not mention Fritz but a variable. I will change that. Gschadow 15:41, 29 September 2007 (UTC)

[edit] Merge

The article is about computer science terms. If anything, they should be merged to Expert system. WLU 22:07, 30 April 2007 (UTC)

[edit] fritz may be a canary

The part of the explanation of the example where it is concluded that Fritz is a frog mentions "and not a canary". I'm pretty sure that we can't actually prove Fritz isn't a canary. We, as humans, intuitively know that something cannot be both a canary and a frog, but there is no rule to that effect in the knowledge base, thus the algorithm cannot conclude it. I think that phrase should be deleted. I'm not going to do it myself because I'm not 100% positive I'm right... 71.88.110.253 (talk) 20:44, 18 May 2008 (UTC)