Science isn't about understanding how something works. It is, as you say, about generating and testing hypotheses. In the case of machine learning, those hypoth

Science isn't about understanding how something works. It is, as you say, about generating and testing hypotheses. In the case of machine learning, those hypotheses take the form of a program and an associated criteria. The hypothesis is verified by demonstrating the efficacy of the program. That a machine learning specialist is able to consistently produce effective programs demonstrates that they have a good understanding of the relationship between the program and its functioning. This is true even if they couldn't explain how the program "works" to the satisfaction of an observer.