"A Discussion between Father and Son"20.

 

 

 

4. “This absorption of the food into the water element inside your body is an
indication that some subtle force is working in you, other than the mere
working of the alimentary canal in your physical body. There are subtler forces.
So from the effect you go to the cause,” says the teacher. “If the food is
dissolved by water and drawn further inward by the action of water and due to
it you feel hungry, even so you feel thirsty for another reason. The water is
absorbed or dried up by the fire principle in your system. The fire draws into
itself the water principle and then you begin to feel thirsty. The water principle
goes into the fire principle. So, finally what remains is a heat in the system and
energy that is generated on account of the food that you eat. So what is the
heat? It is the heat of fire,—in other words, the energy that you acquire due to
the consumption of food. When food is dissolved by water, and water is
absorbed by fire, it is converted into energy in the system. That is why you feel
strong when you take food, and that is also the reason why you feel hungry and
thirsty later on.”

 

5. By way of the analysis of the constituents of the individual, it has thus been
pointed out by Uddalaka, the sage, that everything in this personality is made
up of the essence of the three elements,—fire, water and earth. And what we
call hunger is nothing but the dissolution of the physical food by the element of
water and the absorption of it into the system. What you call thirst is similarly
the absorption of the water element in the system by the fire principle within
us. The effect is consumed by the cause and is absorbed into its own self. This
process continues until all effects are absorbed into the final cause of all things,
where they abide absolutely and completely.

 

 

Chandogya Upanishad: Chapter-2, Section-8, Mantram-4 & 5.