Instinct, intellect and intuition are three different aspects of the mind, or three different modes of consciousness at different levels. The mind is the most important vehicle of the self-conscious thinker or the reincarnating Ego, who functions through it. The mind in man is dual, the higher and the lower. The higher mind is the repository of noble ideas and aspirations which lead the soul to its Divine Parent, Atma-Buddhi. The lower mind is entangled in the lower kamic principle, and both together play havoc on the material plane of life. Though consciousness operates in the different kingdoms of Nature at different levels, endowing them with different powers, self-consciousness, the reflective consciousness, the thinking, reasoning faculty which gives the power of choice and speech, is the prerogative of man. Hence, in the animals only one aspect of mind functions, and that is instinct; and because they do not possess the power to reason, their instinct is purer than that of man. It is an innate power of the divine in them not corrupted by reason. All three, instinct, intellect and intuition, have but one root and source, the divine principle of life and law.

The latent mentality which, in the lower kingdoms is recognized as semi-consciousness, consciousness, and instinct, is largely subdued in man. Reason, the outgrowth of the physical brain, develops at the expense of instinct—the flickering reminiscence of a once divine omniscience—spirit. Reason, the badge of the sovereignty of physical man over all other physical organisms, is often put to shame by the instinct of an animal....Reason is the clumsy weapon of the scientists—intuition the unerring guide of the seer. (Isis Unveiled, I, 433)

Intuition is the right perception of existing things, the knowledge of the non-existent. Whether the knowledge pertains to the physical world or to the inner invisible world, it is clearly perceived and understood. Intuition is looking directly at the ideas behind the words. It belongs to the immortal aspect within each one of us—"the Man that was, that is, and will be, for whom the hour shall never strike." So, intuition is on a much higher level than instinct.

In another place in Isis Unveiled (I, 145), Madame Blavatsky mentions instinct as "the spiritual unity of the five senses" which works when the reasoning faculties seem paralysed and the body is exhausted. Thus, we have not inherited this faculty from the lower kingdoms, but it is divine in essence. At the dawn of manifestation, when the divine life and light differentiates into many, many rays, and each Atmic ray starts its obligatory pilgrimage, that ray develops from itself its spiritual vehicle, Buddhi, which becomes the sixth principle in man. Both together form the Monad, the eternal pilgrim, which completes half the circle of necessity passing through all the forms of life from the most ethereal to the grossest, under natural impulse, in accordance with cyclic and karmic law. It was during this period that the instinctual aspect in man was developed. At this stage, man was only man in form, but not in mind. Spirit and matter had equilibrized in him and he needed the help of the creative hierarchy comprising the mind-born sons of Brahma, who actually incarnated in the most advanced forms and projected a spark in others, thus making of man a thinking being. This was the infancy of humanity when man derived his thinking faculty, his self-consciousness, and became a thinker and chooser. From this point onward, his evolution proceeds through the power of thought, by self-devised ways and means, till he reaches the goal of human perfection. With manasic consciousness added to the Monad, Atma-Buddhi, it becomes the Divine Triad, Atma-Buddhi-Manas. Atma-Buddhi is divine on its own plane, but Manas, the human soul, has to win its divinity and immortality. H.P.B. states in The Secret Doctrine (II, 513) that our mind is "our tempter and Redeemer, our intelligent liberator and Saviour from pure animalism. Without this principle—the emanation of the very essence of the pure divine principle Mahat (Intelligence), which radiates direct from the Divine Mind—we would be surely no better than animals."

This principle of Manas has to make constant effort to unite itself to Buddhi, otherwise it becomes like the cold reason of the scientist. Hence the need to seek always the guidance of the Divine Parent. So Manas is required for Atma-Buddhi, the impersonal Monad, to radiate its divine light. It is the awakening of Buddhi and its conjunction with Manas that brings full enlightenment. Students of Theosophy are advised by H.P.B. in The Secret Doctrine (I, 278): "Since this work withholds far more than it gives out, the student is invited to use his own intuitions." One has to learn to read not only between the lines, but also within the words; to try to get to the ideas rather than be confused over words. This great monumental work was written in a particular manner so as to arouse the intuitive faculty. Average humanity has yet to unfold fully its manasic consciousness, for most men still live on the kama-manasic plane. Therefore, to acquire new ideas and a new attitude is a difficult task for them. It is the inner urge to acquire wisdom, to practise virtues, to become the better able to help and teach our fellow beings that will bring about the needed change. The animal-man has to become truly human, then only he can try to become divine. It is not head-learning but soul-wisdom that is needed on the spiritual path. A devoted and consecrated life may bring us back the knowledge which was ours in former births.

In the earlier races, man had the third or the divine eye, when he was purer in nature. As he left behind that pure stage and as his moral nature was degraded, he lost that power of intuition which we are trying to awaken and regain. It is only true devotion that will bring us back the knowledge which was ours in former births. Theosophy is the quickener of life which has brought us the wisdom of the ages in modern garb. If, with a true heart attitude, those seeds of wisdom are nurtured, our mind will be purified and raised to the higher level of Buddhi-intuition, the power of discernment and discrimination. The pure mind, besides, will help the development of the pure instinct. All three, instinct, intellect and intuition, are necessary on the path of the eternal pilgrim marching towards his own perfection.