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The Expert Systems Era

  1. 01The Expert Systems Era
  2. 02Rules as intelligence
  3. 03MYCIN and the diagnosis machine
  4. 04The expert systems boom
  5. 05The brittleness problem
  6. 06The maintenance burden
  7. 07The LISP machine collapse
  8. 08A quieter failure
  9. 09Reinforce your understanding
  10. 10Question: expert systems
  11. 11Question: brittleness
  12. 12Question: Maintenance
  13. 13Quiz: answer
  14. 14Rules have limits
  15. 15Want to go deeper?
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Module III

The Long Winter

Chapter II

The Expert Systems Era

In this chapter

  • Rules as intelligencewhat expert systems were and how they worked
  • MYCINthe system that tested expert rules against medical diagnosis
  • The brittleness problemwhy they failed outside their rules
  • The maintenance burdenwhy scaling them proved impossible
  • The LISP machine collapsehow the second winter arrived

After a collapse, it's natural to narrow your ambitions.

General intelligence had proved elusive. So researchers tried something more constrained: instead of teaching machines to think, they would give machines knowledge. Specific, careful, expert knowledge, encoded into rules that could be applied to real problems.

It worked. Within the right boundaries, these systems performed impressively. They solved problems that previously required years of training to handle. They found their way into hospitals, factories, and boardrooms. For a time, they were AI's most visible success.

But a system built on explicit rules has a particular kind of fragility. It knows what it knows, and nothing tells it where that ends. Step outside the boundaries, and it doesn't hesitate. It just gets things wrong, with the same confidence it brings to everything else.

Maintaining those boundaries turned out to be its own endless problem. The world kept changing. The rules couldn't keep up.

This chapter is about what happens when a solution that works beautifully in the right conditions meets the conditions it wasn't built for.

Citations