"All human actions are equivalent... and all are on principle doomed to failure"

Carl Sandburg's quote, "All human actions are comparable ... and all are on concept destined failure", provides a rather existential point of view on human undertakings. This statement recommends a philosophical view where every human action, no matter its nature or intent, ultimately carries the very same weight or consequence, resulting in an inescapable failure when seen from a broader, possibly more cosmic, perspective.

To start with, the assertion that "all human actions are equivalent" challenges standard concepts of importance and success. In our daily lives, we tend to categorize actions based on their perceived impact or ethical value. However, Sandburg's viewpoint might be echoing existential or absurdist approach, recommending that in the grand plan-- whether it be a universal, historical, or timeless context-- these distinctions vanish. From this angle, one may analyze that achievements, failures, kind deeds, and misbehaviours all mix into a singular continuum without hierarchy when viewed through the lens of eternity or the limitless universe. It implies a sense of egalitarianism amongst human efforts, where no action is inherently remarkable to another.

The latter part of the quote, "and all are on principle destined failure", even more complicates this concept. It resonates with the idea that human striving is bound to fulfill limitations and flaws inherent in the human condition. This may connect with existentialist themes, where the search for significance, purpose, or permanence is viewed as futile because of life's intrinsic absurdities and the inevitability of death. Failure, in this context, could be analyzed not simply as the failure to achieve specific objectives however the supreme failure to escape the transient, typically disorderly nature of existence.

In summation, Sandburg's quote welcomes consideration on the futility and equality of human efforts. It pushes readers towards a humbling acknowledgment of our constraints and perhaps motivates a form of acceptance. By acknowledging that all ventures may end in failure, one could argue it liberates individuals to act authentically and passionately, unburdened by the fear of supreme judgment or hierarchical evaluation of their actions.