We recognize gradations in consciousness in plant and animal life up through the human being, including gradations of mental power. At the same time, even within a general stage or gradation, we recognise that certain individuals may exhibit different ways of knowing or powers of action, albeit on the same general evolutionary level. At the upper rungs of any particular gradation, we see a fading of the boundary lines as more of the power of the next stage begins to make itself obvious, and we see isolated examples of entirely new developments starting to show themselves as the transition takes place. Each full transition involves a change in the basis of knowing and acting. Life brings an enhanced mechanism of sensation and response/reaction beyond what we see in Matter. Mind brings a new mechanism of knowing not seen in the pure Life stage.
It should be, therefore, no great leap of understanding, to see that at the highest rungs of the mental evolution there would be various gradations that would go from the higher mind functions all the way up to a supramental form of consciousness, and that each of these gradations would take on, successively, various elements of and powers of the succeeding gradation. We may also expect that the next stage of the evolution of consciousness would start from and utilize an entirely different basis than the current mental level. Sri Aurobindo terms this the shift from a consciousness rooted in Ignorance to one based in Knowledge.
Since the evolution takes place based on powers of consciousness that have been involved through various step-down transitions from Supermind to Matter, it is also clear that the variances we can identify occur in both directions as stages of the involution successively distance the self-conscious awareness from the completeness and entirety of the truth, light and full power of existence.
Sri Aurobindo notes: “Still, again there will be a difference between the superhuman and the human, a difference in nature and power but a difference especially in the access and way of admission to the Truth-Consciousness and its activities: there may indeed be two orders of its truth, direct and half-direct, immediate and near or even only a reception at a distance. But this we must consider afterwards; at present it is sufficient to mark certain differences in the descending order of gnostic mind which culminates here. We may say that there is a higher hemisphere of our being in which Mind luminous and aware of its workings still lives in the Light and can be seen as a subordinate power of the Supermind; it is still an agent of the Truth-Consciousness, a gnostic power that has not descended into the mental ignorance; it is capable of a mental gnosis that preserves its connection with the superior light and acts by its power. This is the character of Overmind in its own plane and of all the powers that are dependent on the Overmind: the Supermind works there but at one remove, as if in something that it has put forth from itself but which is no longer entirely itself but is still a delegate of the Truth and invested with its authority. We are moving towards a transitional border beyond which lies the possibility of the Ignorance, but the Ignorance is not yet here. In the order of the evolutionary descent we stand in the Mind of Light on that border and a step downward can carry us beyond it into the beginnings of an ignorance which still bears on its face something of the luminosity that it is leaving behind it. On the other hand, in the ascending order of the evolution we reach a transition in which we see the light, are turned towards it, reflected in our consciousness and one further step carries us into the domain of the Light. The Truth becomes visible and audible to us and we are in immediate communication with its messages and illuminations and can grow into it and be made one with its substance. Thus there is a succession of ranges of consciousness which we can speak of as Mind but which belongs practically to the higher hemisphere although in their ontological station they are within the domain of the lower hemisphere. For the whole of being is a connected totality and there is in it no abrupt passage from the principle of Truth and Light into their opposite. The creative truth of things works and can work infallibly even in the Inconscient: the Spirit is there in Matter and it has made a series of steps by which it can travel from it to its own heights in an uninterrupted line of gradations: the depths are linked to the heights and the Law of the one Truth creates and works everywhere.”
Sri Aurobindo, The Mind of Light, Supermind and Mind of Light, pp. 95-96