No concept better expresses the essence of reality than the Chinese yin-yang. For reality as we know it is nothing if not dichotomized: anything that exists in a way that can be specifically identified or explicitly defined manifests the dichotomy of “to be or not to be” (alive-dead, 1-0, etc.). The irony is that yin-yang is so fundamental to life that we, literate creatures that we are, are driven to construct rhetorically useful but essentially false dichotomies that serve to categorize and hence rationalize our perceptions, as epitomized by Cartesian dualism of mind vs. matter, and by our deeply rooted propensity to view the world as ‘us vs. them’—the source of the ubiquitous straw man.
Nevertheless, I think it safe to say that we can use words to articulate ‘true’ dichotomies that bespeak the fundamental yin-yang nature of reality. One such dichotomy is freedom-constraint. It is yin-yang because you can’t have one without the other. To be free is to be unconstrained, implying (the possibility of) constraint; while to be constrained is to not be free to do something that you would otherwise be free to do. Constraints are real—physical laws such as gravity are examples. If you don’t believe me go jump off a tall building. I suspect you won’t because you know that in reality you are not free to do so without killing yourself. But freedom is real too. You really are free to make your own choices, within the constraints of who you are, where you are, etc. And if you stand atop a tall building and release a bowling ball from the constraint of your hand then it is free to fall to the ground below in response to the constraint of gravity. You are free to decide whether that is something that would be good to do.
Freedom-constraint: everything is free to the extent that it is not constrained. And being granted freedom from one constraint brings into play other constraints that were formerly held at bay (i.e. constrained) by that constraint. If you inflate a balloon and tie off the opening the pressurized gas inside the balloon is constrained from dispersing by the closed elastic wall of the balloon. If you use a pin to burst the balloon you release that constraint, and the gas is now free to disperse in response to (the constraint of) the 2nd Law of Thermodynamics, which compels any unconstrained gradient to dissipate as rapidly as possible.
Another yin-yang dichotomy is rule-exception. Physical ‘laws’ are rules that ostensibly hold without exception. But do they, for all eternity? It seems possible, if not probable, that they did not hold in the earliest moments of the universe, as they had not yet developed into existence. And there may yet come a time, perhaps at the end of time, when they no longer hold, and ‘we’ will once again be free from their constraining influence (only to become constrained by something else currently held at bay by physical law).
Rules are essentially constraints, and exceptions manifest freedom from constraint. Exceptions are the font of creativity. Which brings us to the question of life: is it the rule or the exception? Is life yin or yang? Or is it both?
From the perspective of the science of physics, which is all about rules (physical law), life is clearly the exception. No physical law entails life. The rules of physical science do not foreordain or allow prediction of life. That is not to say that life breaks the rules—it is constrained by them. But if reality consisted only of rules, then there would be no life. Life is constrained by rules, but it is exceptionally creative within those constraints. It is not strictly yin or yang—it embodies both. Since physical science only deals with fully-developed constraints, it fails to grant insight into the creative nature of life. Physical science focuses exclusively on the yang while ignoring the yin. As noted by Jacques Monod in Chance & Necessity (which might as well have been entitled Yin & Yang), the best we can do within the scientific framework is to attribute the creation and creativity of life to the impenetrable mystery of random chance—life's yin to its mechanistic yang. And that is simply another way of saying that insofar as life is creative, it embodies freedom from constraint.