Sri Aurobindo identifies three distinct stages of the functioning of the Buddhi. The first stage is the one that interfaces closely with the sense-mind, organizes the information so obtained and creates opinions and lines of understanding by which to respond to the impressions so received. This stage is therefore intimately connected to the operation of the sense-mind, relies on the impressions that the sense-mind collects and presents, and is subject to the errors inherent in the incomplete or inaccurate reception of data from the senses, which lead to misinterpretation and misapplication by the reasoning intelligence.
Sri Aurobindo notes: “It is not capable of itself forming pure thought and will, but it takes the workings of the higher reason and turns them into coin of opinion and customary standard of thought or canon of action. When we perform a sort of practical analysis of the thinking mind, cut away this element and hold back the higher reason free, observing and silent, we find that this current understanding begins to run about in a futile circle, repeating all its formed opinions and responses to the impressions of things, but incapable of any strong adaptation and initiation.”
In order to shift the functioning of the Buddhi to its further stages it is important to free it from the habitual round of this level of operations. Sri Aurobindo observes: “As it feels more and more the refusal of sanction from the higher reason, it begins to fail, to lose confidence in itself and its forms and habits, to distrust the intellectual action and to fall into weakness and silence. The stilling of this current, running, circling, repeating thought-mind is the principal part of that silencing of the thought which is one of the most effective disciplines of Yoga.”
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 7, Purification–Intelligence and Will, pp. 642-643