Abstractions determine affordances.
Each level of abstraction becomes an opportunity to make work more efficient, communicate more clearly, and assist understanding.
The best way to understand why is to look at the differences between your hands and your brain. Your hands can’t change size, but your mind can: if you’re paying attention, your brain becomes more keen to experiences over time. So while the size of an aspirin pill is constrained by your stubby little fingers, your brain can normalize the patterns of an interface and make way for more nuanced abstractions. With enough time and exposure, a user can shed the padding and metaphors that become dead weight, like taking the training wheels off a bike.
This notion of movement is presented in screens that offer affordances. The movement defines what things are. They define or inform on the functionality.