From the 13^th verse to 19^th verse, Lord Krishna is introducing the fourth topic, jñeyam.  The word jñeyam means that it is to be known by everyone, the ultimate truth of the universe.  Every human being wants immortality; therefore, everyone should know this truth.  This is brahma vidya. 

Verse 14

It has hands and legs everywhere.  It has eyes, heads, and mouths everywhere.  It has ears everywhere.  It remains pervading everything in the world.

In the Upanishads, brahman is defined as basic essence, the ultimate content of the universe.  All the sciences are also trying to find out the ultimate substance of the universe.  Initially, they thought that the whole universe is made up of combinations of elements.  Then they arrived at molecules; thereafter they said that all the molecules are made up atoms and the whole universe is invisible atoms in motion, creating a visible universe.  Thereafter, the scientists broke the atoms into particles and that was the ultimate substance.  Then they divided the particles, and they thought the energy is the ultimate substance of the universe.  As you go deeper, the visible becomes invisible, tangible becomes intangible; concrete becomes abstract.  Scientists have not yet arrived at the final answer.  But Vedanta has arrived at Brahman as the ultimate substance of the creation; being the ultimate substance, Brahman will be abstract, intangible, invisible with no form, sound, smell etc. Therefore, understanding Brahman will be difficult because it is not available for touching, smelling, or seeing.

We see lot of substances in the world like “a tall man”.  We use a noun and an adjective to describe a substance.  Adjectives reveal the property of an object.  Nouns reveal the substance.  Let us take the example of a golden bangle or a wooden chair.  Bangle is noun and golden is adjective.  The word golden does not refer to the property but the very substance of the bangle.  Gold is the substance of the bangle.  In this case, adjective reveals a substance but not a property.  In the example of a tall person, tall reveals a property.  An adjective can reveal either a property or a substance.  Bangle is a noun, but it does not reveal a substance, because there is no substance called bangle.  There is only a substance called gold.  Then what does the word bangle refer to?  When the gold is in a particular form or shape, then that shape alone is called bangle.  Bangle is only the form or shape of the substance; the name of the substance is gold.  Bangle is the name of the form only and the form is changed when the gold is melted.  Adjectives reveal property or substance.  Nouns can reveal adjectives or property.  Examples:

• Adjective revealing Property:  Tall
• Adjective revealing Substance:  Golden; wooden.
• Noun revealing Substance:  Tree
• Noun revealing the property: Bangle, chair.

When I experience the world, for example, there is a wall.  The verb “is” points to existence.  Examples are there is a tree, there is a man.  Everything you experience in the world is an existent object.  If anything is non-existent, then we will not experience it. 

What is the noun and adjective in the sentence “there is a man”.  The word existent is adjective and man is the noun.  What type of adjective and noun it is?  An adjective can reveal a substance or property; The word existent adjective reveals the property or the substance?  Until we come to Vedanta, our conclusion is that the world is the substance and the word existent is an attribute or property.  Vedanta says that is the work of Maya.  Maya makes you commit a big mistake of making you think that the existent adjective is not revealing the attribute, but the substance or according to Vedanta, Sat Brahma.  Existence is the fundamental, absolute substance and as a result is invisible, intangible and abstract, without form or any other property. 

If the adjective reveals a substance, according to Vedanta, every noun reveal a property; bangle is not the substance, but the shape of the gold, substance is gold.  The whole world is not a substance at all but a different name and form.  Existence is the only substance.  When you are experiencing different objects, you are experiencing the fundamental substance; when you are experiencing a chair, you are experiencing the wood. So, when you experience world, you are experiencing the basic substance, existence, Brahman.

You are experiencing the basic substance, the existent with different name and form; existent is never experienced in pure form, but only with a name and form through my sense organs.  Sense organs are equipped to experience only substances with properties – shape, name, smell, taste etc.  How can I experience pure existence?  When you remove all the name and form, what is left behind is pure existence.  But the sense organs can never experience the pure existence.  To experience the ultimate substance, close all your sense organs, what is left behind is basic substances which is pure existent.  How do you experience the pure existent without any sense organs?  You can never experience pure existent because it is not an object of experience.  Then how do I know it is there?  It is you, the witnessing consciousness. Pure existence is nothing but pure consciousness and that is me, the existent consciousness.

The example given in the Upanishads is dream experience. A dream is capable of frightening you, but when you are in dream, you are the essence of the dream world, the dream world is resting on you and on waking up the dream will go away,  When you are in dream, it is very difficult to accept that.  But when you wake up, the dream world will not exist. It is difficult to accept that the dreamer is the substance.  During the dream it is difficult to accept that I am the dreamer.  Similarly, it is difficult to accept that I am the substance of the world.  That “I” is Brahman and that Brahman is existent and that Brahman alone appears with different nama roopa. Just as gold is inherent in all ornaments, existent is inherent in all objects.  If an object does not have existence, it is a non-existent object.

Verse 15

It is manifested through the functions of all organs.  Yet it is free from all organs.  It sustains everything.  Yet is unattached.  It is the experiencer of gunas.  Yet it is free from gunas.

All the sense organs reveal Brahman all the time.  Eyes can reveal only color, but not sound.  Ears can only reveal sound but not color.  All the sense organs experience one thing in common, that is existence.  They all reveal uniformly Brahman.  But we are attracted by nama roopa and lose sight of the inherent existent substance, Brahman.  But due to the mixing up of nama roopa, we miss the substance.