Instinctive behavior takes place, as it does in the plant and animal development, in the human being as well. There are numerous built-in patterns of reaction that help to define how the human individual will respond to various circumstances or situations. At the same time, we see in the human being the development of the power of the mind, and with the advent of self-reflective operations of intelligence and reason we see the conscious effort to modify or suppress the action of instinct and supplant it with a decision made through the mental process. This action of the reasoning intelligence disrupts the pure reaction of instinct. There are both positive and negative aspects of this disruption. The human being acts as a transitional being with the capacity and drive toward a greater fulfillment and a greater action of self-awareness and self-exceeding towards a higher range of consciousness. To the extent that instinct hinders or gets in the way of this process, it must be addressed. At the same time, the mind tends to try to dominate the physical and vital segments of the human composition, and due to its limitations, it may suppress or try to eliminate powers that are necessary for the completeness of the expression, rather than adjust and reorient them.
Sri Aurobindo observes: “The being of man also is full of physical, vital, emotional, psychical and dynamic instincts and intuitions, but he does not rely on them as the animal does,–though they are capable in him of a far larger scope and greater action than in the animal and lower creation by reason of his greater actual evolutionary development and his yet greater potentiality of development of the being. he has suppressed them, discontinued their full and overt action by atrophy,–not that these capacities are destroyed but rather held back or cast back into the subliminal consciousness,–and consequently this lower part of his being is much less sure of itself, much less confident of the directions of his nature, much more groping, errant and fallible in its larger scope than that of the animal in his lesser limits. This happens because man’s real Dharma and law of being is to seek for a greater self-aware existence, a self-manifestation no longer obscure and governed by an ununderstood necessity, but illumined, conscious of that which is expressing itself and able to give it a fuller and more perfect expression. And finally his culmination must be to identify himself with his greatest and real self and act or rather let it act (his natural existence being an instrumental form of the expression of the spirit) in its spontaneous perfect will and knowledge.”
To do this, the use of the reasoning intelligence is the first and foremost tool to begin with. But due to the limitations of the reasoning intelligence and the circumscribed capacities it has, this is not sufficient nor the ultimate tool for development beyond the human limitations. “The godhead of the reason, the intellectual Logos, is only a partial representative and substitute for the greater supramental Logos, and its function is to impose a preliminary partial knowledge and order upon the life of the creature, but the rael, final and integral order can only be founded by the spiritual supermind in its emergence.”
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 19, The Nature of the Supermind, pp. 766-767