What's wrong with expert systems?

In the early days, thought to be wonderful. Particularly because

• They could generate their own explanations.

• The knowledge is modular: it's easy to add rules, and each rule corresponds to a nice little chunk of knowledge that an expert knows.

But there are problems. This leads to the subject of human-computer interaction amongst other things.

• Maintaining large knowledge bases
• Strategy and questioning
• Explanations
• Shallow reasoning
• Lack of common sense, and restriction to narrow domains
• No learning
• Systems aren't adaptable