KATHOPNISHADA CHAPTER 5 SHLOKA 4

                                                                अस्य विस्रंसमानस्य

                                                                शरीरस्थस्य देहिनः । 

                                                               देहाद्विमुच्यमानस्य

                                                        किमत्र परिशिष्यते। एतद्वैतत् ॥ ४

                                                    

                                                     ASYA  VISRAM  SAMANASYA

                                                        SHARIRASTH DEHINAH |

                                                    DEHAD  VIMUCHYAMANASYA

                                                     KIM  ATRA  PARISHISHYATE ||

                                                                 ETAD VAI TAD ||4

WHEN IT (ATMAN) WHICH DWELLS IN THE BODY (PHYSICAL BODY) LEAVES THE 

                        BODY   THEN  WHAT REMAINS? THIS VERILY THAT ||4

    This Shloka is the answer to the question that Nachiket had asked . What happens when some one dies. Nachiket wanted to know as to what happens when people say he is dead as the physical body is still there. The Lord of Death is telling us and Nachiket that when the Atman leaves the physical body, nothing remains or what remains is of no importance or use. We all know this fact. Once the life is gone the physical body decays. So indirectly He is differentiating between the physical body and the Atman. The Physical body is a vehicle and by itself it can not do anything. The Atman is the main things due to which the physical body function.. If the Atman is gone then there is no use of physical body. It os like any electrical instrument. The computer will not work without the electricity, even though it still has hardware and software. So physical body is like hardware . The electricity is needed to run it or do the job . butt electricity itself does not do any of the computer work . The same electricity will be needed for light bulb to give light and TV to work and show us the TV programs - images and other things. But the electricity by itself is not TV or light bulb, So the electricity is needed for the function of all these equipment but the electricity itself does not do the work of these equipment. Similarly the Atman is needed for physical body to perform it's function, but it itself does not do the functions of this body nd when it leaves there is no function that physical body can do. .

     The mind has two way connection. One way is towards the physical body and other way is the connection is to the Atman. In reality there is no connection as such but the Mind FEELS that way . When the mind along with intellect and Chitta  and the Atman and Causal body THE KARAN SHARIR leaves the physical body, the connection of Mind with physical body is gone. But the Atman and connection  of mind  to Atman is still there . The Atman is the cause of functioning Mind. If there is no Atman there is no mind functioning. So the physical body dies but the Atman and Astral body and the Causal body they all continue..