Those who are intelligent, they are not concerned either for living hundred of years or hundred thousands of years. They want to live perpetually, eternally. That is intelligence. Because I am eternal: na hanyate hanyamāne śarīre (BG 2.20).
I will not die. Not I, every one of us—nobody will die. Na jāyate mriyate (BG 2.20). We have no death, no birth; simply we are changing this body just like we daily change our dress. So one has to stop. This is perfection of life. This repetition we don't like. Suppose if somebody comes and asks you, "Please die immediately. I shall give you a body of King George V," or something like that. Would you like to? Would you agree? Why? If the promise is that "You give up this body, and I will give you another body, a king's body or a demigod's body, or you will live for one thousand years or one million years." So perhaps we may agree that, but we are not agreeable to give up this body immediately, because we do not like. That is our natural instinct. We do not wish to die; therefore we are afraid of death. We do not like to change, because we are eternal. That is the reason. The background is because we are eternal, therefore we do not wish to change. We want to build . . . the scientists are trying to live forever. They say that, "By science we shall make everyone living for good." But that is not possible. If you want to live for good, in blissful life and full of knowledge, then you have to transfer yourself from this material world to the spiritual world. There it is worth it. There your natural life, mad-dhāma gatvā punar janma na vidyate. The Bhagavad-gītā says: "Anyone who comes to Me, he does not come back again on this material world." Duḥkhālayam aśāśvatam (BG 8.15): this material world is full of miseries and also temporary.