Proposition 1) It’s all a construct in your mind.
I know that sounds trippy, but it’s true. Of course, the real world, with its laws of physics still applies. These laws are not a construct, at least for now, at our current state of development.
There’s also science, which attempts to explain and understand the world around us. These disciplines enhance our understanding of reality, but they do not represent our internal construct.
What you think of as reality, is really just your internal “map” of your existence in the world as you understand it.
Proposition 2) Since it’s a construct in your mind, and since we know we have some degree of neural plasticity, it can be altered.
Successfully treated mental illness might be a useful example of this. The afflicted’s sense of reality is distorted, but with the proper motivation and treatment, the distortions can be revealed and corrected. Obviously this is not completely possible for everyone, yet it is absolutely true for some (important caveat: like life itself, this is an ongoing process).
My overarching point here is this: For the purpose of our internal consciousness, what you believe to be true is true. We each possess an internal locus of control, whether we choose to exercise it or not.
To a certain degree, we control our own destiny by what we believe we are capable of.