Balance is the designated state of a system wherein the energy flows are regulated sufficiently by controls. Such controls estimate error and make compensatory adjustments so as to constrain system changes to remain within acceptable parameters.

In the context of the intrinsically chaotic cosmos, it is a mischief to suppose that any equilibria are stable. Stability is a state related directly to a timescale and often ignores the reality of cosmic instabilities. The fishtank may appear to be in stable equilibrium for the moment but the next volcanic eruption or local six point five Richter earthquake may revise opinions on that.

The continued existence of a living entity is contingent upon it being able to compensate for deviations from any balanced state and thereby deferring catastrophe. It must have the capacity to adjust its circumstances when confronted by any general process or random capriciousness in order to neutralize the effects sufficiently to sustain continuity. If it is hungry it must acquire food. If it is injured it must be able to repair the damage. If it is confronted by any one of the innumerable unpredictable dangers of nature it must have an avoidance strategy or perish.

Unbalanced systems are always constrained by the more general rules of a wider nature if the internal control systems prove to be inadequate. A disintegrating super-nova does not trigger the obliteration of the entire cosmos. An exploding species population is ultimately constrained by the limits of the biosphere. Any greatly deviant individual will soon attract the attention of the custodians of normality. Get the balance sheet on a transparently even keel, or the enterprise will incur the displeasure of the shareholders, or the tax department, or the government, or all three. Control the growth of a cancer, or the death of the individual will ensure the constraint of its expansion.

Humans frequently suppose certain systems to be balanced or not by adopting whatever self-serving parameters suit their purpose. Mechanical and electrical systems, political and social institutions, mental states, eco-systems, bodily functions...etc... can be deemed to be in balance or not according to the parameters which are assumed as significant. The parameters chosen for an air-conditioning system to be supposedly balanced, are not always happily accepted by those having to live in the building. The introduction of species into an ecosystem in an attempt to restore some perceived imbalance is often anything but beneficial. Opinions as to the mental states of other individuals may or may not have validity but procedures introduced to correct the supposed imbalance are usually more satisfying to the administrators than the afflicted.