llm-workshop-2025

The Bitter Lesson

Rich Sutton | March 13, 2019

The biggest lesson that can be read from 70 years of AI research is that general methods that leverage computation are ultimately the most effective, and by a large margin.

In computer chess, the methods that defeated the world champion, Kasparov, in 1997, were based on massive, deep search. At the time, this was looked upon with dismay by the majority of computerchess researchers who had pursued methods that leveraged human understanding of the special structure of chess. When a simpler, search-based approach with special hardware and software proved vastly more effective, these human-knowledge-based chess researchers were not good losers. They said that ``brute forceā€ search may have won this time, but it was not a general strategy, and anyway it was not how people played chess. These researchers wanted methods based on human input to win and were disappointed when they did not.

A similar pattern of research progress was seen in computer Go, only delayed by a further 20 years. Enormous initial efforts went into avoiding search by taking advantage of human knowledge, or of the special features of the game, but all those efforts proved irrelevant, or worse, once search was applied effectively at scale.

This is a big lesson. As a field, we still have not thoroughly learned it, as we are continuing to make the same kind of mistakes. To see this, and to effectively resist it, we have to understand the appeal of these mistakes. We have to learn the bitter lesson that building in how we think we think does not work in the long run. The bitter lesson is based on the historical observations that:

  1. AI researchers have often tried to build knowledge into their agents,
  2. this always helps in the short term, and is personally satisfying to the researcher, but
  3. in the long run it plateaus and even inhibits further progress, and
  4. breakthrough progress eventually arrives by an opposing approach based on scaling computation by search and learning.

The eventual success is tinged with bitterness, and often incompletely digested, because it is success over a favored, human-centric approach.


Original article: The Bitter Lesson