Page 424 - Complete Works of Dr. KCV Volume 1

But there is an impulse in the entire organism which is in nature at the beginning but aims at integrating its nervous paths with all the other systems (through exercise) thus making for coordinated action which shows the absolute vitality of purposive action in all evolution and integration. The same purposiveness which appears as the adjustment to the environment in the animals appears as consciousness and will in men and also as the integrative power which affects the entire associative tracts in the brain and links them together powerfully. It is that again which seeks to make the consciousness dominant in actual life. It is consciousness or more truly spirit that seeks motor expression and in its expressing it 'stoops to conquer!' its own earlier manifestations. The Sukshma (subtle) is an earlier stage in evolution than the sthula (gross) according to the upanishads. The sukshma has the psychonic system - which expresses the antah karana (internal organ) and its phases and whose centres are placed along with the chakras within it and connecting with the physical organs placed at those places respectively.
But accustomed as we are to the physical alone we have left behind the sukshma conceptions and think in terms of gross neural systems and therefore the whole of Yoga philosophy and practice seeks to influence the direction of the physical by making the sukshma more efficient and vital with regard to our life and experience. This means the recognition of the theory which postulates the transmission of energy from the neural to the psychonic and from the psychonic to the neural systems reciprocally, till finally they are completely integrated. This also means perfect sensibility and perfect knowledge and conscious control. In a sense, the psychon and the neuron are next brothers being born from a more primary element say Akasa or ether.
Thus the latest theorists in psychology reveal the anxiety to re-embrace consciousness into psychology, which had first lost its soul and then its mind in recent years thanks to the Behaviourists. Lest finally consciousness the epiphenomenon, should also be crucified. Dr. Mc. Dougal and Dr. Marston have brought out a psychonic theory which may yet save consciousness to psychology.
Endocrine theory of chakras.