You may ask the question, "At what stage will he attain true satisfaction? How will he obtain it? Material science explains that in the brain of human beings there 4 types of waves alpha, beta, tetha, and delta. With a velocity of 0.5 to 4 cycles per second, they are the cause for peace , restlessness and satisfaction. According to material science, in the right side of the brain are the delta waves and the other three waves reside in the left side. For this reason we feel a lack of peace. But if were to raise the delta waves in the left side then satisfaction can be obtained. This is called "a state of inert'' according to the language of science. When one atom is not completely stable due to a lack of electrons, it begins to revolve, and sometimes is attracted to and sometimes repelled from other atoms. But when this atom is completely stable, then according to the rules of orbit 2n squared (n = number of orbits) if he attains the full amount of electrons, he becomes completely inert.
According to material science, Helium, Krypton, Arshon, Neon, Genion, Radon, etc. are inert gasses that never join with atoms. In the same way delta waves never join with alpha, beta and tetha waves. You may ask how is it possible then for delta waves to come to the left side of the brain. Yoga sastra explains three types of nerves, ingla, pingla, and susumna. When susumna is active, the delta waves are active in our brain. In yoga sastra it is explained that there are many processes to activate the susmna nerve by many types of yoga processes, i.e. asans, pranayam, dhyana ( posture, breath control, meditation) etc. These things were explained to Arjuna by Krsna in the Bhagavad Gita 6.13-15.
saman kayo-siro-grivam
dharayann acalam sthirah
samprekesya nasikagram svam
"Keeping one's body, neck and head erect and steady, one should fix one's vision solely on the tip of the nose. Thus, following strict celibacy, becoming fearless, peaceful and controlling the mind, one should practice yoga by meditating on Me with one-pointed attention, remaining always devoted to Me."
disas canavalokayam
prasantatma vigata-bhir
brahmacari-vrate sthitah
manah samyamya mac-citto
yukta asita mat-parah
"Thus, constantly keeping the mind absorbed in Me through yoga by following the process, a yogi whose mind is controlled, can become situated in My svarupa (nirvisesh Brahma) and attain santi in the form of complete emancipation."
yunjann evam sadatmanam
yogi piyata-manasah
santim nirvana-paramam
mat-smstham adhigacchati
"Thus practicing control of the body, mind and activities, the mystic transcendentalist attains to the kingdom of God [or the abode of Krsna] by cessation of material existence."Thus yogi concentrate his mind on the goal and then his pran-vayu (incoming breath) and apan-vayu (outward breath) come to an equilibrium. Without this equilibrium the susmana nerve is not activated. So yogis perform pranayam ( breath control) to open this door, and by chanting the mantra AUM they become liberated from material things and obtain their goal.
Bg. 6,13-15
In bhkati-yoga however we chant:
Hare Krishna Hare Krishna,and achieve our ultimate goal, which is Krsna-prema. Then we are completely satisfied.
Krishna Krishna Hare Hare,
Hare Rama Hare Rama,
Rama Rama Hare Hare