Commonsense Reasoning: An Event Calculus Based Approach
This repository contains my notes, exercise solutions and practice codes based on the contents of the book Commonsense Reasoning: An Event Calculus Based Approach by Erik T. Mueller.
Fundamental entities:
- Objects (and object identity)
- Properties that change over time (such as location)
- Events or actions (we must also be able to represent the effects of events on the properties, and events that are nondeterministic or context-sensitive)
- Time
- Space
- Preconditions (if the robot put the book on the table, it had to be holding it beforehand)
- Law of inertia (things do not move by themselves): If something (non-living object) has moved, then it has been moved by someone or something.
- Delayed effects and continuous change (the tap is left open and the sink fills up with water and overflows)
- Reasoning: It takes a representation as an input, and outputs a representation
Default reasoning: We assume a default (or normal) state of the world. Even though several exceptions might occur, the most usual (or most probable) state is considered to be the default state used for the default reasoning. The default assumption is that unexpected events do not occur.
Mental States: Common sense assumes that if an agent has an unsatisfied goal, it will come up with a plan to achieve the goal.
Types of Reasoning
- Prediction (also called temporal projection): reasoning about states resulting from events
- Abduction Given an initial state and a final state, the reasoning is done by forming a path of events.
- Postdiction: Given events that lead to another state, we have to reason about the state prior to the events.