From a therapeutic perspective, hypnosis is an internally focused state of mind which is entered intentionally in order to achieve positive behavioural and experiential change. The hypnotic state can be achieved either alone through the process of self-hypnosis or through direction/guidance/suggestion by way of a hypnotist. In both cases an internal focus is achieved by the person in hypnosis wherein the subconscious mind is rendered open to inquiry, suggestion and change. It is this process which has been shown to be capable of bringing about lasting change in waking conscious experience and ongoing behaviour.
From a scientific perspective, the neural mechanism (that which is believed to be taking place cerebrally during hypnosis) is currently a mystery which will remain so until more light is shed on the relationship between the brain and the mind. There is a further, perhaps unsolvable, problem here in that there is no scientific consensus as to precisely what the mind is or how it works. In our attempt to understand the relationship between the brain and the mind we find that two very different disciplines are involved: psychology and neural science. Since both of these disciplines are constantly evolving there are currently many theories available from which to choose and these are being added to continuously.
What is the mind and what is consciousness?
The human organism is the most complex entity of which we are aware in the entire universe. Conversely, the current ideas regarding the structure and mechanism of the mental element of this fantastic beast are reminiscent, in their crude simplicity, of something made out of a child's building blocks.
In hypnotherapy the mind is generally divided into a hierarchy of levels of consciousness. The experiential part of this, the part to which we are privy, the part that believes it made the decision to pay a visit to the hypnotist or to read this book, is called the conscious mind. Underneath this is the aptly named subconscious. Some also term this level the unconscious whilst others regard the unconscious as being below the subconscious. Some believe there are further levels. Some believe that each or all layers of consciousness are divided into parts which may be addressed separately as if they were individual entities. Some hypnotherapists believe there is a base level to all of this which they call the core.
There is no openly examinable evidence for any of these models of the mind and each quickly displays its shortcomings when searching questions are asked.
Is the self of the conscious mind the same self as the unconscious or subconscious mind? Is the conscious mind simply a caricature, a puppet that suffers the whims of the careless, disinterested subconscious mind, until the hypnotist intervenes on behalf of that conscious mind. Is the subconscious mind unaware of conscious experience? If so, why should this be the case? If it is aware of conscious experience (that is the experience the conscious part of the mind is said to have) then why should it need encouragement to bring unpleasant conscious experience to an end?
Nobody can really offer universally acceptable answers to these questions or if they can they are either keeping this to themselves or what they have discovered is simply uncommunicable.
The model of the mind as used in hypnotherapy is basic and almost certainly inaccurate due to its elementary nature but it does seem to provide a useful enough framework for hypnosis to work.
There is another deeper and perhaps unanswerable question that arises when trying to understand the human individual. In the final analysis what actually am I? What are you? What is the self, this self that is said to have a mind that may or may not be split into various levels of varying awareness of various things?
Do these questions matter? Were clients of a mind that they needed these questions to have satisfactory answers before agreeing to undergo hypnotherapy then few sessions would take place. But we don't need to supply satisfactory answers to these questions. Hypnotherapy works - mainly.
How? We've no idea.