Backward Chaining


Backward chaining is a method used in artificial intelligence and logic programming, where you start with a goal, and then work backward to find the necessary steps to achieve that goal. Instead of moving from cause to effect, it goes from effect to cause. This technique is commonly used in expert systems, diagnostic applications, and theorem proving.


The phonetic pronunciation of “Backward Chaining” can be represented as “ˈbæk.wərd ˈtʃeɪ.nɪŋ”.

Key Takeaways


  1. Backward Chaining is a method used in artificial intelligence for establishing goal paths. It works by beginning from the end goal and working in reverse to find out what actions would lead to that goal.
  2. This approach is also highly beneficial in scenarios where the number of solutions to reach the goal is comparatively small. It’s an efficient method for solving complex problems as it quickly narrows the search path.
  3. While Backward Chaining is efficient and effective in many scenarios, it also relies on the assumption that an end goal is known and definitive. For problems where the end goal is unclear or which need explorative thinking, this method may not be as applicable.



Backward Chaining is a significant concept in the field of technology, particularly in artificial intelligence and programming. It is a method used in logic programming and inference-based AI systems where the process begins with the goal and works backward to infer the data or facts that led to that conclusion. This approach aids in decision-making, problem-solving, or rule-based systems. For instance, in expert systems or goal-oriented programming, where different conditions or knowledge-based rules are applied to reach a solution, backward chaining proves vital. It allows these systems to streamline their processes and make their approach more efficient, resulting in a more reliable outcome or solution. Thus, the concept of backward chaining underpins the functionality and effectiveness of many AI and logic-based systems, thereby underscoring its importance in technology.


Backward Chaining is predominantly used in artificial intelligence as well as machine learning where it serves as an inference method. Its purpose is to enhance the efficiency and effectiveness of the decision-making process. Backward chaining starts with a list of potential goals or end results and systematically works backward to determine whether there is any feasible data or evidence to support them. It assumes that if the derived consequence is true, then the conditions that led to it within the set of rules must also be true. In practical terms, backward chaining is a method that is used in rule-based expert systems, programming, problem-solving and game theory. Considered as a “goal-driven” strategy, it’s commonly utilized when there are numerous outcomes that are driven by fewer conditions. Thus, its usage not only simplifies and improves the probabilities of reaching an outcome, but it also provides a comprehensively structured and systematic pathway to attain the result. Notably, in the field of teaching and behavior analysis, backward chaining is used to help students or subjects learn new skills by working through each step of a desired outcome in reverse order.


1. Medical Diagnostics: In healthcare, medical experts often use backward chaining to diagnose patient illnesses. The system starts with a list of symptoms (the end goal), then works backwards to identify likely diseases or conditions. This method has been utilized in the development of AI platforms like IBM’s Watson, which helps doctors analyze symptoms to arrive at potential diagnoses.2. Legal Professions: Lawyers often use backward chaining in their legal reasoning. This technique is useful when trying to prove a case or make an argument. Lawyers start with the desired result (such as a guilty or not guilty verdict) and then work backward searching for pieces of evidence or arguments that might lead to this conclusion.3. Natural Language Processing: Backward chaining is used in NLP algorithms to predict or generate sequences in language-related tasks. For instance, in writing suggestion tools, the aim might be to complete a sentence. The system could start with the sentence’s end and work backward to provide appropriate suggestions based on context, syntax, and grammar rules.

Frequently Asked Questions(FAQ)

Q: What is Backward Chaining?A: Backward Chaining is an inference method in the field of artificial intelligence, which is commonly used in logic programming and various kinds of problem-solving applications. It starts with a list of goals and works backward to solve the problem.Q: How does Backward Chaining work?A: Backward Chaining works by beginning at the goal, or final conclusion, and works backward to find the necessary data or facts to support the conclusion. If other conclusions or conditions are needed, the chain will continue backwards until the original data is reached.Q: What are the benefits of using Backward Chaining?A: Backward Chaining is ideal for complex problems where there are too many facts to consider. By starting with the end goal, Backward Chaining allows for a targeted approach in searching for the solution.Q: Is Backward Chaining used only in AI?A: No, Backward Chaining is not only used in AI but also in various domains like game theory, theoretical computer science, and teaching methods. In AI, it is commonly used in expert systems.Q: Can you give an example of Backward Chaining?A: Sure, an example of Backward Chaining is its application in medical diagnosis. It starts with the symptoms (the goal) and works backwards to identify the disease (the cause).Q: What’s the difference between Backward Chaining and Forward Chaining?A: Backward Chaining starts with the goal and works back towards the facts, while Forward Chaining starts with the initial data and works forward to find the goal or conclusion.Q: What do we need in order to apply Backward Chaining?A: To apply Backward Chaining, we need a list of rules or knowledge base and a clear end goal or conclusion. If the goal is complex, we might divide it into several sub-goals and solve them one by one.

Related Technology Terms

  • Inference Engine
  • Knowledge Base
  • Goal-Driven Reasoning
  • Expert Systems
  • Deductive Reasoning

Sources for More Information

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