It is at the level of mental energy that we can recognize the moral principle in its true and pure sense, not watered-down by the type of compromises that arise under the banner of morality in the world of life action. This moral principle is not based on the seeking for or achievement of rewards in life, or on the avoidance of pain and suffering in life. Rather, it is something that is sought solely on its own behalf, as something that is right and true and which fulfills the “categorical imperative” that the principle holds on the mental plane.
The karmic return achieved by following this principle is not any longer the achievements of wealth, physical well-being, or social status and respect; rather, it is the growth of the soul.
Sri Aurobindo elucidates this further: “Mounting here the ethical mind no longer follows good for a reward now on earth or in another existence, but for the sake of good, and no longer shuns evil for fear of punishment on earth later on in this life or else in another life or in hell, but because to follow evil is a degradation and affliction of its being and a fall from its innate and imperative endeavor. This is to it a necessity of its moral nature, a truly categorical imperative, a call that in the total more complex nature of man may be dulled or suppressed or excluded by the claim of its other parts and their needs, but to the ethical mind is binding and absolute.”
Traditional morality, relying on reward and punishment, is a low-burning flame that is subject to being smothered by the demands of life situations and can even be seen as an obstacle to the establishment of a true morality based on the principle, not on some temporary accommodation. “Whatever its practical utility or service as a step of the transition, the mental habit of confusion and vitalistic compromise it fosters and the more questionable confusions and compromises that habit favours, have made conventional morality one of the chief of the forces that hold back human life from progressing to a true ethical order. If humanity has made any lasting and true advance, it has been not through the virtue created by reward and punishment or any of the sanctions powerful on the little vital ego, but by an insistence from the higher mind on the lower, an insistence on right for its own sake, on imperative moral values, on an absolute law and truth of ethical being and ethical conduct that must be obeyed whatever the recalcitrances of the lower mind, whatever the pains of the vital problem, whatever the external result, the inferior issue.”
Sri Aurobindo, Rebirth and Karma, Section III, Chapter 16, The Higher Lines of Karma, pp. 145-146, http://www.lotuspress.com/item.php?item=990117