Many students are exceptionally confused by the concept of abstraction. I searched around for a way to explain this more effectively. Lo and behold, I found a video presented on YouTube that does a pretty great job of clarifying the concept of abstraction, which is outlined on page 75 of your textbook.
I remind you as always that watching a video or attending a lecture is not a substitute for reading the book. Be a responsible consumer of the course materials, and use these things to supplement your text.
Anyway, here’s the video on Language, Thinking and Levels of Abstraction:
I SHOULD warn you that the best part of the explanation is within the first 3 1/2 minutes, but you can watch the full 6’36” video to better understand the concept.