And if ' ability to maintain itself ' is seen as a positive property : There still exist an untold number of species of so-called ' low organisms ' which can maintain themselves perfectly well (such as bacteria, or coelenterates [jelly-fishes, polyps] ), often much better than the so-called higher organisms.
The essence of complexity might (among other ways) be investigated along the concepts of ' algorithmic complexity ' and ' logical depth '. Here it is important to clearly distinguish between the epistemological and ontological aspect. In a metaphysical consideration it is the latter that counts.