The integration of the mental energy into the world of life follows a similar model to the integration of the life energy into matter. There is an initial stirring of the mental force, a reaching out, an inquisitive seeking, an attempt to understand the framework within which it is enclosed and the way its power can be exercised successfully. Subsequently, we see the mental energy engaging with the world of life and matter, gaining a deeper understanding of their functioning and beginning to exercise an increasing measure of influence or even control in that field. It is at this stage that the mental energy begins to provide serious returns in the form of more precise and powerful action, and, to the extent the life energy and physical matter have been properly understood, at least to some degree, a more successful result.
It is after the mental energy has engaged in this way that it begins to create for itself a uniquely mental space in which it can organize and express itself without concerning itself directly with the affairs of the world, and it is at this point that we see the functioning of the truly mental force in its native power and energetic action.
All along the way we see the basic principle at work that the greater the mental energy, the more knowledge is applied to the life efforts and the world repays this with results. In fact, the power of applied knowledge shows a much greater and more direct payback than other mental forces such as the moral or ethical energy that also stems from the mental realm.
Sri Aurobindo draws the following conclusions on this point: “In this material world it is at least doubtful how far moral good is repaid by vital good and moral evil punished by a recoil, but it is certain that we do pay very usually for our errors, for stupidity, for ignorance of the right way of action, for any ignoring or misapplication of the laws that govern our psychical, vital and physical being; it is certain that knowledge is a power for life efficiency and success. Intelligence pays its way in the material world, guards itself against vital and physical suffering, secures its vital rewards more surely than moral right and ethical purpose.”
Sri Aurobindo, Rebirth and Karma, Section III, Chapter 16, The Higher Lines of Karma, pp. 150-151, http://www.lotuspress.com/item.php?item=990117