The physical body (actually the entire material world) is subject to habits, and change tends to come slowly. Our being, however, is made up of a series of sheaths which progress from the subtle to the gross physical and thus, any attempt to make a change to the more outward sheaths, the physical, the vital and the mental included, must begin at the more subtle levels of the inner being. The more subtle an energetic field is, the more pliable it can be, and the more powerfully it acts upon the next more outward sheath.
We see this principle illustrated in the outer nature. While the physical body undergoes change slowly, the vital body is subject to impulsive shifts of direction, mood and energy. The more these coalesce around a coherent subject, the more they exert a change on the physical. Thus, when a person attempts to lose weight, for example, the physical habit tends to maintain the weight, but a vital enthusiasm for a new diet may override the inertia of the physical body and implement changes that can lead to short-term weight loss. When the enthusiasm subsides, however, it is possible for the physical body to reassert its habit if the change has not gone on long enough to actually effectuate a real and lasting change in the physical habit. Thus, the phenomenon of “yo yo dieting” has been understood. The vital nature has its habitual patterns which can tend to get locked in and resist change over the long term.
Similarly, the mind is capable of adopting new understanding and concepts and working to apply them to the vital and physical world. The changes wrought by the mental power on the outer world are evident and obvious to everyone living in today’s world. Yet, the mind too has its habitual patterns and is particularly susceptible to linear forms of thought that do not recognise the unintended consequences of actions in the world, or the interrelated complexity of the being upon which it is trying to impose its will..
All of these however remain focused at the surface level of our being. More subtle, and more powerful, are the inner levels of consciousness, which are also capable of direct linkage to the universal forces of creation. When we begin to recognise the need for a change of consciousness to effectuate the real and necessary changes required to meet the existential crisis that we are facing in the world today, we awaken to the need for the development of a new standpoint and power of action independent of the surface ego-personality working through the surface mind, life and body. The inner being, with its ability to receive direct influences from the wider, universal nature, is the conduit through which change can be implemented.
Sri Aurobindo notes: “What you say about the outer being is correct, it must change and manifest what is within in the inner nature. But for that one must have experiences in the inner nature and through these the power of the inner nature grows till it can influence wholly and possess the outer being. To change the outer consciousness entirely without developing this inner consciousness would be too difficult. That is why these inner experiences are going on to prepare the growth of the inner consciousness. There is an inner mind, an inner vital, an inner physical consciousness which can more easily than the outer receive the higher consciousness above and put itself into harmony with the psychic being; when that is done the outer nature is felt as only a fringe on the surface, not as oneself, and is more easily transformed altogether.”
Sri Aurobindo, Integral Yoga: Sri Aurobindo’s Teaching and Method of Practice, Chapter 7, Experiences and Realisations, The Inward Movement, pp. 174-179