When I first was introduced to the concept of monkey brain thoughts, I was fascinated. We have these instinctive sorts of mental processes for keeping us alive and functioning, but they don’t always work properly, and they aren’t what separates us from other animals. Higher thought moves us forward.
But then, a lot of what we “think” ends up being regurgitations of things we’ve been taught, or facts memorized through rote. So beyond the basic monkey brain, and this quasi-memorization, you can finally get to original thought. If such a thing is actually possible.
This is a three-level structure, but by Googling “levels of thought” you quickly find varying degrees of systems, from two levels all the way up to seven (that I saw in a cursory search). So, much like Descartes, who postulated “I think, therefore I am,” it seems not just me, but many of us are fascinated by the various aspects and nuances of thought.