As Sri Sri Ravishankar says, there are seven levels of existence,
Meditation works by bringing an effort from the level of being to the mind. With the breath we bring this effect to the physical level as well.
Hereis a nice and very informative page on the seven levels, http://www.meaningoflife.i12.com/7levels.htm
And if Maslow's Hierarchy of Need comes to your mind looking at lower levels of these seven levels, then it should be also clear that human moves to higher levels. Probably the goal of human life to attain the top most level.
Read some more Sutras of Sri Sri, http://www.angelfire.com/me2/sutras/ssrs.html