Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
When I refer to your "ego barrier," I'm referring to your subliminal defense mechanisms that make it hard for you to accept your mistakes and weaknesses. Your deepest-seated needs and fears--such as the need to be loved and the fear of losing love, the need to survive and the fear of not surviving, the need to be important and the fear of not mattering--reside in primitive parts of your brain such as the amygdala, which are structures in your temporal lobe that process emotions. Because these areas of your brain are not accessible to your conscious awareness, it is virtually impossible for you to understand what they want and how they control you. They oversimplify things and react instinctively. They crave praise and respond to criticism as an attack, even when the higher-level parts of the brain understand that constructive criticism is good for you. They make you defensive, especially when it comes to the subject of how good you are.
At the same time, higher-level consciousness resides in your neocortex, more specifically in the part called the prefrontal cortex. This is the most distinctively human feature of your brain; relative to the rest of the brain, it's larger in humans than in most other species. This is where you experience the conscious awareness of decision making (the so-called "executive function"), as well as the application of logic and reasoning.