Bakåtföring

Bakåtföring is a term used in Swedish to describe a reasoning or inference method known in English as backward chaining. It is a goal-driven approach in logic, knowledge representation and artificial intelligence, where the reasoning process starts from a desired conclusion and works backward to identify the facts or rules needed to support that conclusion. This contrasts with forward chaining, which moves from known data toward conclusions.

The concept originates in logic and expert-system literature and is commonly discussed in texts about rule-based reasoning. In bakåtföring, the system proposes a hypothesis or goal and then recursively checks which rules or known facts would need to be true for that goal to hold. If an applicable rule’s premises are not yet established, the process continues by seeking evidence for those premises, potentially expanding the search tree until the goal is supported or disproved.

Applications of bakåtföring include diagnostic reasoning, theorem proving, and other knowledge-based tasks where the objective is to determine whether a specific conclusion can be justified given a set of rules and facts. It is particularly useful when the goal is known or suspected in advance, and the task is to demonstrate its validity rather than to enumerate all possible outcomes.

Limitations include potential computational cost and the risk of exploring irrelevant branches if the knowledge base is large or poorly organized. Effective use often requires well-structured rule sets and strategies to manage recursion, avoid cycles, and control the breadth of the search.

See also: backward chaining, forward chaining, rule-based reasoning, knowledge representation.