Herbert Dreyfus factors this problem into three parts (1992, p.xviii):
- How every day knowledge must be organised so that one can make inferences from it.
- How skills or know-how can be represented as knowing-that.
- How relevant knowledge can be brought to bear in particular situations.
The last problem has been called the access problem, that is, the problem of how to efficiently access data in a knowledge base.
The access problem is also relevant to heuristic search [see the Heuristic Search arguments on this map], because in large knowledge bases the problem of accessing informaiton is also the problem of searching for it.
Comonsense knowledge is defined as: Our everyday understanding of the world. Generally such knowledge consists in pretheoretical information that seems obvious when explicitly stated, for example: our knowledge that tables generally have four legs and are something people put things on, or that people generally bring gifts to birthday parties.
It has been said that commonsense knowledge consists not of the information contained in an encyclopedia, but rather in all the information necessary to read and understand an encyclopedia in the first place.