Most people mistake Yang and Yin as opposites. Hot and cold; night and day; hard and receptive. Each sounds like the opposite end of a spectrum. But it's more accurate to speak of Yin and Yang as complements. One doesn't make sense without the other; they complete the spectrum and provide meaningful context for all of the in-betweens.
Yang is action. Yin is substance. In the beginning, when nothing else existed, Yang was the impulse to make something out of nothing and Yin was the something that longed to be made. Two halves of one whole, each lurking within the other. Activity without substance is pointless. Substance without activity is worthless. So the two existed within the one, which was the thought that brought them together.
Thinking makes it so.
The thought of activity within substance brings that substance to life. The thought of substance within action brings that action into context. Thought is the beginning and the end of everything that results.
How you think - the way your mind is wired - defines the story of your life. Not a little bit, but completely. Information flows in from outside your mind, but all of it is acted upon by your mind before you accept or reject it. Which is a roundabout way of saying that there is no actual outside influence on who you are or what you make of yourself in this life.
You collect the data; you reject the data; you interpret the data; you invent, seek out or refine the data. You tune it out; you dial it up. You are the source of all thinking that choreographs the way Yin and Yang transform into your experience.
This is true whether you're consciously engaged or not. If you're stressed out, suffering, apathetic, bored, frustrated or overwhelmed, you're not yielding enlightened thought to your destiny. If you're turned on, congruent, empowered or, at the very least, interested, then you're consciously creating something worthwhile. You are the Big Bang.