Perspective and/or focus determines definition. Another way to say this is that in order to more exactly define what something is, you must more exactly define what it is not. All aspects of existence exist as themselves and as the opposite of themselves, how different the opposites are is determined by how closely the focus is placed on something unique. If something is in a state of being that something, then it, itself, creates a "need" for it to be the opposite of itself. This is a concept of balance, a state not of rest nor of excitement, but as both. Both cannot exist only as one and the same thing without change though, for then this would be rest. In other words; no absolute balance exists, for if there is a state of balance, that state of balance, itself, creates a need for imbalance, in order to create a "more full" ("on a higher level", "one step up", more totally encompassing) global state of balance.
This goes on indefinitely, if there is balance on one "level", then imbalance is created on the next level up so that that higher level is now balanced... and so forth. You can see this in thinking about possibility and impossibility: if an occurrence is exactly half possible and half impossible, this is a state of balance; yet whether the occurrence occurs or not has to do with the global possibility or impossibility in which the local possibility/impossibility exists, and how that effects it. Theoretical example: you spin a coin, only this a coin with super-duper razor sharp edges (only two outcomes). Let's say you spin it amazingly even, and when it's just about to stop and fall, it is precisely perpendicular to the spinning surface. This is a local state of balance. Whether the coin falls on one side or the other now depends on the global environment (the surface being on a small slant, air pressure, and earthquake...). This happens at every level.