Computer have an entirely deserved reputation for lacking “Common Sense”. An AI program may passes more knowledge than an accounting program but it still computers using primitives that it knows nothing about. Consider the following interaction between a Medical Diagnosis System and a Human.
System: How old the patient?
System: Are there any spots on patient’s body.
Human: Yes (Notice rust spots)
System: What color are the spots?
Human: Reddish Brown.
System: The patient has measles (Probability 0.9).
Obviously, the system does not really know what measles are, or what the difference between ears and people is. Ever with in its speciality, the system is unaware of fundamental facts. For Eg. That Human have two arms. Clearly what the system lacks is knowledge. No of AI techniques that can be used to enable an AI program to represent and reason with Common Sense Knowledge.
For example in predicate logic one can state facts such as “If you die, you are dead at all later times.”
Frames can describe everything objects and scripts can describe the typical sequence of events. Non-monotonic logics can support default reasoning, an important aspect of common sense.
Memory is another key aspect of common sense. We look at how a memory can organize experiences, generalize them and use them to solve new problems.