This theory that originates from Gurdjieff and Ouspensky (and has roots in the Pythagorean theories of harmonics) says that every process is formed of seven stages of development and that there are two discontinuity points that need an energy boost or a shock to continue.
Those seven stages were symbolically associated to the musical octave from "do" to the next "do".
On an octave, the first shock is to be delivered between "si" and "do", that is, at the end of one cycle and the beginning of the next one.
As the energy of the beginning may run out quite quickly and the process might not be completed, a second shock is to be delivered between "mi" and "fa", which is 3/7 of the whole cycle.
If you think about the 7 musical tones in association with the 7 chakras of the energetic body, you will notice that there is something special between the 3rd chakra (solar plexus chakra) and the 4th chakra (heart chakra), as there is indeed a wall, a separation. On the physical level this wall is the diaphragm, that separates the abdominal cavity from the thoracic cavity – the first 3 chakras are located below the diaphragm, the next 4 chakras are located above it. On the spiritual level, there is a separation between working to fulfill one's basic needs (first 3 chakras: food/money, sex/social acceptance and trust/personal power) and working to fulfill one's spiritual needs (love, sensibility/intuition, knowledge/understanding, bliss).
Using this knowledge and applying it back to the moment of the second shock (3/7 of any cycle), one can understand that the second shock should be spiritual in nature and is essential for an integrated living, for the unity between the material and spiritual sides of our beings or of any life experience.
In astrology, on the zodiacal circle, this beginning of the cycle is 0 Aries, which corresponds to the first shock in the Law of Seven theory (or the first influx of physical energy).
On the zodiacal circle, the location of the second shock is 04 degrees 17 minutes and 08 seconds in Virgo (which is 3/7 of the 360 degrees).
Look at the Sabian Symbol associated to this point: A MAN BECOMING AWARE OF NATURE SPIRITS AND NORMALLY UNSEEN SPIRITUAL ENERGIES (5 Virgo).
The moment when the Sun transits this special point is called the yearly solar hiatus and represents a special moment when one's spiritual activity may be particularly efficient to help having a fulfilling life experience (for the remaining of the year) and generally boosting one's spiritual life.
I feel that the hiatus moment is really important to help integrate the spiritual aspects of any life experience, so that it might really get us to the next spiritual level.
You may perform a meditation or any other spiritual activity the next times when the Sun transits that special point:
in 2009: on August 27, at 10:15 am GMT
in 2010: on August 27, at 04:07 pm GMT
in 2011: on August 27, at 09:57 pm GMT
in 2012: on August 27, at 03:45 am GMT
in 2013: on August 27, at 09:41 am GMT
in 2014: on August 27, at 03:22 pm GMT
You may study the moment of the needed 2nd shock of any cycle, such as the monthly Sun-Moon cycle. To Hindus, the day when that happens is celebrated as the day of the goddess Tripura Sundari (two days before the Full Moon), the goddess of love and harmony.
The Law of Seven and the concepts of the 1st and the 2nd shock that are needed to get processes started and then finalized explain very well the critical degrees in astrology.
The 30th degree of any sign (29:00 - 29:59) is a critical degree because the 1st shock (energy boost) is needed to get new things started. This is the energy of the beginning.
The critical degrees associated with the limits of the Moon's mansions (12-13 and 25-26 in cardinal signs, 8-9 and 21-22 in fixed signs and 4-5 and 17-18 in mutable signs) are critical degrees because the Moon mansions' length is 3/7 of the length of a Sun sign, therefore at these points a 2nd shock (energy boost) is needed to prove one's worthiness to finalize the process. This is the main spiritual test to face on the path.