We are spiritual beings, which means we are capable of many different kinds of choices. It is true that our human brains, being complex adaptive systems, operate within a certain set of dynamics that define or constrain our choices. For example, our brain systems are geared to insuring survival, so they instinctively generate reactions of fear and anger in the presence of perceived threats, and that “default” mechanism may sometimes compromise our ability to choose how we might respond to a given situation. Our brain systems also have far more functions to fulfill than they have the energy to fully undertake, so they often default into an “overwhelm” mode, which we experience as such in our conscious minds as well. These, and many other similar systems constraints, often affect our abilities to make informed, thoughtful choices.
By the same token, these ingenious brain systems are also responsible for generating “conscious minds”, which provide us with the capacity to become fully aware of our circumstances and to reflect thoroughly on who we are, what we want, how best to achieve that, and other similar considerations. In short, as humans, we have the unrestrained capacity to take stock of what is going on in our lives at any given moment, put aside all the habitual, unconscious behaviors that might have historically governed our responses to date, and choose a new, independently derived behavior.
Engaging in such “awareness” exercises also awakens our minds to the further possibilities that exist in consciously choosing how we might respond to others or specific challenges in our lives, what thoughts and feelings we might want to occupy our minds, or what new approach to life we still might like to try. This is what I call “existential choice”, because it represents the capacity to define—and continuously redefine—how we perceive ourselves and our lives, the people we encounter every day, and what we plan to do with the time we have left.
This type of existential choice eventually allows us to realize that there is no "external reality" that operates on us like some Newtonian system of action and reaction, but that instead it is the power of the human mind and the exercise of existential choice that creates our reality. Not only the “reality” that we experience in the dynamic interior of our minds, but also the larger “reality” that exists for all of humanity, within a “system” of life that is defined not by Newtonian physics but by the mysterious, ever-changing world of quantum mechanics, where systems are not even definable until they are measured or "observed". We are all "observers", charged with the responsibility of choosing well and fully exploring our spiritual nature in order to create a meaningful reality for all.