Because that’s what it has been called since the term was coined in the 1950s. I think its meaning may be shifting, but https://en.wikipedia.org/wiki/Machine_l

Because that’s what it has been called since the term was coined in the 1950s. I think its meaning may be shifting, but https://en.wikipedia.org/wiki/Machine_learning#Artificial_intelligence https://en.wikipedia.org/wiki/Machine_learning#Artificial_in... still shows it as a broader term than “machine learning”, including expert systems. Also note that decision tree learning (https://en.wikipedia.org/wiki/Decision_tree_learning https://en.wikipedia.org/wiki/Decision_tree_learning) basically is a search for a good rule-based system.