The mental force interacts with the physical world and the vital force to create a “mixed” action. This action can enhance the results achieved by the vital force. It can also interject mental principles into the action that can begin to add a moral or ethical element to the striving of the vitality. Morality is not a principle of the vital force, per se. As has been discussed previously, the fruits of success in the vital action go to those who have the best understanding, strength and conditions for that success. The advent of mentality adds another condition or element to the striving for success, by creating moral or ethical rules which create a framework within which the vital force is then permitted to operate. This does not mean, however, that the distinction between the mental force’s action and the results on the vital level can be blurred or glossed over. The mixing of the mental and vital yields a much more nuanced and complex result.
Sri Aurobindo delves into this issue: “At first sight, if success is the desideratum, it is not clear what morality has to say in the affair, since we see in most things that it is a right understanding and intelligent or intuitive practice of the means and conditions and an insistent power of the will, a settled drive of the force of the being of which success is the natural consequence. Man may impose by a system of punishments a check on the egoistic will and intelligence in pursuit of its vital ends, may create a number of moral conditions for the world’s prizes, but this might appear, as is indeed contended in certain vitalistic theories, an artificial imposition on Nature and a dulling and impoverishment of the free and powerful play of the mind force and the life force in their alliance. But in truth the greatest force for success is a right concentration of energy, tapasya, and there is an inevitable moral element in Tapasya.”
Sri Aurobindo, Rebirth and Karma, Section II, Chapter 15, Mind Nature and Law of Karma, pp. 132-133, http://www.lotuspress.com/item.php?item=990117