...fish are the best swimmers. They were born and reared in the water, but do they know the role of the water? Humans are the best walkers. They were born and raised in the air, but they do not know the role of the air. One thing they share: if the fish are plucked from the water, they will die; and if man is displaced from the air, he will also die. Water and air are different, but the need for them is the same. Man and fish are different, but if you change their positions the result will be the same; that is, man must have air as fish must have water. Therefore, my idea of swimming on land is appropriate. Man on land is swimming in the air, but he has long forgotten about it. No doubt you don’t know the role of air. Great Air contains everything. The role of air is to imbue everything and sustain all materiality. People know the results but not the mechanism.
Cheng Tzu's Thirteen treatises, Cheng Man Ching
The oxygen in the air plays an important part in sustaining animal life, and the carbon plays a similar part with plant life, but Vital Force has its own distinct part to play in the manifestation of life, aside from the physiological functions. Air contains more than oxygen, hydrogen and nitrogen and does more than oxygenate the Blood. Animal and plant life breathe Vital Force in with the air. If the air did not contain it, they would die even though they a may be filled with air. It is taken up by the system along with the oxygen, and yet is not the oxygen. Continue reading Air