Coherence (lat. Cohaerere, cohere) is an essential point of view in psychology and psychiatry, under which the formal thought processes of patients are judged (see mental disorder).
Here, coherence means that the train of thought - apart from the subjects and facts formulated in terms of content - is in itself logical, coherent, and comprehensible.
Coherence of brain waves (in reality, scalp currents are measured - the brain itself could only be observed roughly over tomography with contrast media, more recently also by laser technology) is a modern topic in neurology.
In humans as well as in many animals there is a sense, a neurobiologically central sensibility for constructive (coherent connection, inside or eg also in the social systems) innate. Our brain follows the organizational principle of self-referentiality.
In medicine there is coherence for optimal synchronization of the rhythms of heart beat, respiration and blood pressure (cardiac coherence).
In physics, coherence means frequency- and phase-equivalent waves, for example laser light waves, or quantum mechanical states.
In the narrower sense the semantic context of the words in a text; in a wider sense, the term coherence also encompasses the syntactic relationships between sentences, for example, anaphor, cataphor.
If the TM-movement shows an increased coherence of scalping currents (!) during the pseudo-flying, I think it is a bluff because the body is not relaxed during the hopping movement. The measurements of such currents were never proven and made by members of the movement, just like real flying was never never shown - in TM - films it suddenly goes.
The electrodes would have to be glued or a special helmet put on (which happens nowadays). Paper is patient and can not resist, and what is to be held by statements of interest representatives and profiteers is .....
Apart from that, coherent currents occur in all areas of life and in much greater magnitude without affecting the environment.
Consciousness is a controversial term. The Vedanta distinguishes four states of consciousness: Vaishvanara, the waking state, Taijasa, the dream state, Prajñā and Turiya (the fourth).
The average meditator first experiences the chitta of the mental plane. Only the Shabda of the true Samadhi contains a state of nondual consciousness.
Maharishi propagated seven states of consciousness (Video 1 ; Video 2 -> there are also parts 3 to 5 of the video), first up to a cosmic consciousness and then to a consciousness of God (which corresponds to the Ishvara consciousness of step 19 of the universal path), but such masters are different structured than Maharishi, and which, in my opinion, he does not have. After this comes a unity consciousness (for this: Principles of MVS).
The Mandukya Upanishade deals with them in detail. The four states of consciousness (Avastha), which are also described in Shivaism, are also called Jagrat, Svapna, Sushupti and Turiya. In the Yogasystems also further stages (Bhumikas) are described.
Certainly, coherence does not mean a Samadhi (as a so-called misinterpreted fast fourth TM - consciousness - state) or Turiya, which is in combination with concentration (dharana) and meditation (dhyana) as Samyama the prerequisite for propagated Siddhis like foam-rubber flying.....
Patanjali warns before the binding and hindering effects of such forces. Only a very advanced yogi is at all capable of doing so. A uplifted coherence with alpha waves as sign of deep relaxation can definitely not bring such states. Despite from that the method of measurements have never been put open - and i think that they are a fake of popcorn-science !
In the meantime severeal neurologist measured that gamma waves are more relevant, which occur not only in Vipassana of progressed vajrayana monks, but also in lucid dreaming and much less during TM-meditation.
Patanjalis Ashtanga yoga is a step-by-step process that had long before been described in the Sandilya Upanishade of Atharvaveda.
This eightfold path is also explained in Yoga Yajnavalkya, in several Upanishads and in other writings such as Devi Bhagavatam 7.35, Sivasamhita and Hathapradipika.
Today's Shankara Order also represents the steps of Ashtanga Yoga and does not dispense with the first three steps: "Ashtanga Yoga--Yama, niyam, aasan, praanayaam, pratyaahaar, dhaarnaa, dhyaan, samaadhi.
These are the eight limbs of yoga. A guru takes a student one by one through them. For this, the Guru takes nothing from his disciple. He does it out of kindness and from the feeling of doing something good for his student." Shree Shankaracharya Swaroopanand Saraswati (The Illustrated Weekly of India, September 13, 1987)
Patanjali writes in the Yogasutras III (On the Supernatural Forces: Vibhuti Pada ) :
4 These three (dharana, dhyana, samadhi) are collectively referred to as "collection" (samyama).
5 Their mastery leads to view of wisdom.
6 It is applied to the different areas.
7 These three (dharana, dhyana, samadhi) are the inner core of the earlier aspects of Yoga (ie. yama, niyama, asana, pranayama and pratyahara)......
19 Applying the "collection" (samyama) to experience, one gets knowledge of the thoughts of others.
20 But not (you get knowledge of) the basis of these (thoughts), since it cannot become an object.
21 But not the basis of this, since it can not become an object.
22 Applying the "collection" to the appearance of the body, the power that makes it perceptible is banned and the connection between the eye and the light is interrupted, and it becomes invisible .....
44 Applying the "collection" to the coarse form, the self-being, the fine form, the relation and the meaningfulness of the elements, one gains mastery of the material world.
45 This results in supernatural abilities, such as making the body atomic small, etc., perfection of the body and inviolability in the physical properties.
A Man and the nature
1 The wonderful abilities (siddhi) are either congenital or they arise through (medicinal) plants, through sacred words (mantra), through asceticism or through meditation.
If everything were so simple, India would be the land of the Siddhas. Certain siddhi-like abilities are also found in the sphere of occult magic - even without enlightenment.
It is also unexplained how the alleged coherence and deep relaxation during TM - meditation can be sustained during the straining foam rubber contractions.
Therefore i personally go out of manipulated measurements (ala Popcorn science), as long as the measurements have not been certified by a recognized independent institution.