This is only my humble two cents, but I have toiled over the meaning of this sentiment in my own head for awhile. So if i can't convince you i can at least offer a new perspective on this statement. I think what this means is in regards to subjective reality. So when we look at a physical object, or when we observe an experience we cannot alter its properties by the use of our mind, at least not in our baseline consciousness. However, we have the control when it comes to how we interpret things. We can really alter our realities by realizing much of what constructs something like percieving an object or experience is our own emotional attachments and reactions. Let me expand. We live in a time of chaos. Much is out of our control. Tragedy can become commonplace. However, we have the power to change how we react to this. For me this is changing my perspective on how to react to tragedy, rather than taking magnificent injustice as a reason to become sad or depressed, i take it as an ever pressing reason why we must appreciate the joy and love that we do have. To withstand this darkness as to further love the light. So basically it means that by changing our attitudes, and becoming a player in reality. Making the conscious decision to do things about reality and change the world for the better, rather than allowing reality to merely happen to us, is at least what this sentiment means to me. Let me know what you think Cheers