Kinds of Knowledge
Several kinds of information need to be represented:
Long-term Knowledge: This is accumulated knowledge about the world. It can include simple data, general rules (every person has a mother), programs, and heuristic knowledge (knowledge of what is likely to work). The collection of long-term knowledge is often called a knowledge base (KB). Human long-term memory seems unlimited, but writing to it is slow.
Current Data: A representation of the facts of the current situation. Human short-term memory is very limited (7 ± 2 items).[Miller, George A., ``The magical number seven, plus or minus two: some limits on our capacity for processing information'', Psychological Review vol. 63, pp. 81-97, 1956.]
Conjectures: Courses of action or reasoning that are being considered but are not yet final.
These will be represented in a knowledge representation language. Questions that are not directly in the KB may be answered by inference.