[Question] What ML gears do you like?

In John’s recent post he mentions many people in ML not having good gears level models of what’s going on.

To wit; what gears-level models do you know for ML? How much support is there for them? Are there “settled science” kind models that have tons of empirical support?

What gears-level models informed the people who made major AI advancements? Is there a list, or writing about this somewhere?