Western psychologists describe the mind as having two main divisions, the conscious and the unconscious. (The usage of 'unconscious' in this respect is therefore different from that used previously.) The conscious mind is predominant during our normal waking state. It is this part of the mind that analyses, compares and reaches conclusions in relation to incoming information. Problem solving and intellectual thinking are the characteristics of this rational state of mind. It is a cliché to compare the mind to an iceberg. The conscious mind is the tip that appears above water; the bulk of the iceberg hidden beneath the surface is the unconscious mind.
Anyone can confirm from his own experience that the conscious waking mind is not the only field of mental activity. It is a common experience to find we are unable to remember something, no matter how hard we try. Then later, when we least expect it, that thing which slipped our memory before spontaneously comes to mind. We often have dreams involving forgotten persons or scenes from childhood. Sudden inspirations come to us, seemingly from nowhere. There are many such ordinary examples that point to the existence of some other, deeper mental force working behind the waking mind.
Following Freud, psychologists claim that the unconscious is the storehouse of all past experiences. Those experiences which were particularly painful are pushed deep into the unconscious, beyond remembrance. Such repressed experiences are still active and are the source of our fears and obsessions. Also within the unconscious are our instinctive desires, constantly in competition for expression and satisfaction through the conscious mind. It is within the tumultuous unconscious mind that we find the roots of our tensions.
Between the conscious and the unconscious is the logical, rational part of the mind that Freud called the 'ego'. This is the 'censor' part of the mind, for it allows only a refined trickle of information into the conscious mind and blocks off any material it considers unsuitable. The censor serves a necessary function in allowing us to concentrate on the work we are doing. It shuts out all irrelevant information from the senses, and admits to consciousness that information which is concerned with the work in hand.
The censor functions as ego because it identifies the complexes, inhibitions, likes and dislikes which contribute to the egotistical nature of the individual, and it feeds the conscious mind with information that will satisfy these restrictions. For example, if we fear something, that information which reinforces that fear will rise to conscious perception earlier than information which would indicate that this thing is not so fearsome after all. Likewise, information that does not reinforce these preconceptions is energetically restrained from becoming conscious. The censor is constantly engaged in maintaining the suppression of many drives and desires that are irrational and/or impractical, and cannot be given expression within the bounds which are established by the conscious mind.
The very bias of the censor, our ego, prevents us from seeing the world clearly and objectively, and this continually influences our emotions and reactions to the external world, because the unconscious is always active, even during sleep. Censorship and repression represent a misuse of our personal resources by consuming a great deal of energy that could be usefully directed elsewhere. We are also denied access to those areas of the unconscious that are the seat of intuition and creativity, and to the collective unconscious, which contains the inherited experience of the race. Jung saw this latter as the part of the mind that links us to other human beings because it contains the record of our common past. While some censorship is necessary for effective functioning, too rigid censorship cuts us off from parts of our minds that are positive and insightful.
Yoga nidra helps us bring the conscious and unconscious minds into harmony, and so leads us to a state where censorship is not necessary, at least temporarily. Information from the senses is shut off, the censor is off duty, and we are led in a systematic exploration of the unconscious.
What man is unable to express in words, he makes into symbols and myths which, taken at surface value only, may appear fanciful or meaningless, but these symbols contain in concentrated form the essence of experiences too deep for logical comprehension. The unconscious mind stores experiences and finds expression through symbols and images. We most frequently experience this when we dream. Within our unconscious are the personal symbols of our individual existence, and many symbols that have powerful and common significance for all people. These symbols have different meanings -some relating truths of the spiritual life, some arising from the basic conflicts of humanity, and others that exist to allow the unconscious part of the mind a vehicle for expression and relief of tension.
During the practice of yoga nidra, we are able to observe the play of these symbols and images. This leads us to greater understanding of our real nature, and reduces the conflict between the unconscious and conscious parts of our minds.
During yoga nidra and other forms of meditation there is a slowing down of the whole metabolism, indicated by reduced oxygen consumption, increased skin resistance, decreased heart rate and increased alpha wave activity in the brain. Blood pressure also drops, but because of the reduced constriction of the blood vessels there is a greater flow of blood throughout the body. This increased blood flow is responsible for the efficient delivery of oxygen to the muscles to break down the lactate that has accumulated during muscular activity. This is important, for medical tests show that a build-up of lactate in the system results in increased fatigue and anxiety. This kind of physiological change normally takes place during deep sleep but only after some hours. The practice of yoga nidra takes up a state of relaxation that is deeper than sleep, thus allowing these changes to take place in a short period of time.
Such complete physical relaxation prepares us for investigation of the deeper levels of the unconscious mind. Normally our awareness is blocked off from these regions by the efforts of the ego to cope with the conflict between the unconscious and conscious minds. During the practice of yoga nidra we switch off from extroverted waking consciousness. We are asked to lay aside the intellect and to function only on the level of feeling. The ego no longer has to satisfy the critical intellectual consciousness, and so ceases to censor the impulses bubbling up from the unconscious mind. We can look at tension as the accumulation of repressed energy that powers those drives and desires that are denied satisfaction through the conscious mind. During yoga nidra these frustrations and thwarted desires are given expression so that tension is reduced and the energy behind these desires is freed for use in other directions.
This process, too, takes place during normal sleep when we dream. However, insufficient or inadequate sleep means that we need more dream time to cope with the turmoil in the unconscious. Yoga nidra brings us to a state of 'self-induced' dreaming, with a difference, Regular dreams are composed simply of a random selection of unconscious impulses. During yoga nidra we create a 'dream' according to the guide's instructions. The symbols chosen for this practice have powerful universal significance, and so are especially useful for increasing awareness and relieving tension. When we regularly review the contents of the unconscious in this way, we greatly reduce anxiety and bring our inner being into greater harmony. This counteracts pessimism and depression and increases the efficiency and joy with which we perform our daily work and play. Life truly becomes an expression of physical and mental health.