By this time you will have recognized that the human body is like a machine, and a very efficient one.
It consists of many different systems, each carefully interwoven with, and interdependent on, the other. Standing in supreme command is the giant computer like object we call the human brain. This automatically acts as captain of the total working machine. Whether we are awake, asleep or half-conscious, it continues to carry out a multiplicity of functions quite automatically.
Many of these operations are totally out of our power to control or alter. For example: the normal beating of the heart and circulation of the blood, normal respiration, the digestion of food, the manufacture of blood and new cells in all parts of the body. These simply occur automatically, and without our conscious mind playing any part whatever.
A certain number of functions are within our range of command. But the desire to perform these is generally governed by the “computer.” For example, if we are thirsty, this fact registers, so we have a glass of water. If the body starts to fall short of fuel, we sense hunger, so tend to seek food and eat it. If we are tired and exhausted (indicating the need for body repair and replenishment of’ vitality), we instinctively wish to lie down and sleep to accomplish this necessary repair.
So, in a sense, we have a degree of control over what we do. But this degree is limited in extent, and is essentially governed by our automatic “computer.” The example of thirst and its quenching has already been mentioned. But we do not continue this process indefinitely. When the system has acquired enough to meet the immediate needs, the brain sends out the message that we have drunk an adequate amount. So we stop.
The same applies to the intake of food. If we foolishly ignore the messages from the higher centers then the same system soon rebels and lets us know. For eating or drinking to excess may be followed by a sudden feeling of nausea, and vomiting may ensue. Anyone who indiscreetly overindulges (such as small children at a party, where they often make gluttons of themselves) knows the penalty, and how uncomfortable this is. This is one of the controls of the brain also. There is a penalty for disobeying its instructions!
Certainly we have the conscious ability to determine how we fulfill some of these computerized instructions. For example, the brain does not give explicit instructions on what we should eat and drink. So, we frequently indulge in foods that are far from nutritious. We might overeat spicy foods or greasy preparations that we know are not good for our particular digestive system. Many indulge in alcoholic beverages, frequently to excess, in the hopes of “getting a kick” and “feeling good.”