The very fundamentals of spiritual longing are to transcend the limitations of the physical. For an individual, the most intimate part of physical creation is his or her own body. So the very basis of a spiritual process is to explore the possibilities of the body and to go beyond its limitations.
Your physical body is designed and structured to function by itself without much of your participation. You do not have to make your heart beat or your liver do all of its complex chemistry. You do not even have to breathe; everything that is needed for your physical existence to manifest itself is happening by itself.
The physical body is a self-contained, quite complete instrument. And if you keep it well, you may go through your whole life without ever having a spiritual longing because the body is so complete by itself. If you are fascinated by gadgets, there is no better gadget. Every little thing you explore in the body is quite incredible. But it takes a certain amount of intelligence and awareness for a person to see the limitations of this fantastic gadget. Gadgetry is fine, sophistication of mechanism is fine, but still, the body does not take you anywhere, it just springs out of the earth and flops back into the earth.
Can this be enough? If you look at it from the perspective of the body, it is quite enough. But a dimension beyond the physical somehow got trapped in the physical. This dimension, without which there is no life, has somehow been infused into the physical; life is one thing, but the source of life is another. And the source of life is functioning in every plant, seed and creature. In a human being, the source of life has taken on a higher presence. So for humans, all the simple or even wonderful things that the physical offers at some point become irrelevant.
Because the source of life has taken on a higher presence in a human being, one is in constant struggle between the physical and that which is beyond the physical. Though you are physical, you are also in contradiction with the physical. Though you have the compulsiveness of the physical, you also have the consciousness of not being physical.
Any kind of method or spiritual process you employ to heighten the presence of that which is the source of creation within you is referred to as “yoga.” Such methods and processes become necessary because of what seems to be a fundamental conflict between the instinct of self-preservation and the longing to become boundless. These aspects are not against each other, but when you look at it from the perspective of the physical, when your whole perception is limited to the physical, they seem to be in conflict. One force belongs to the physical; the other belongs to the dimension beyond the physical. If one has the necessary awareness to separate the two, there is no conflict. But if one does not have this awareness, if one is identified with the physical, there appears to be a conflict between these two fundamental forces.
If you go by the ways of the body, it knows only self-preservation and procreation. These are the only two aspects of the body. If you go by the dimension beyond the body, the longing is to become boundless. So the instinct of self-preservation and the longing to become boundless come in conflict because of a strong identification with the physical. One force helps you root yourself well on this planet; the other is supposed to take you beyond. Instead of working in collaboration, they become in conflict. All the struggles of humanity in terms of “should I be spiritual or materialistic” are just coming from this.
Unfortunately, when one tries to find physical expression to this longing to become boundless, it usually leads to various types of insatiable activity (e.g., the pursuit of money, power, love, pleasure, property); one always wants to be a little more than who one is right now. So this is a never-ending longing, but this longing is not just seeking a little bit more, it is seeking ultimate expansion. This is the longing of the limited to expand or evolve into the unlimited.