Actually, we are not subject to death. That is affirmed in the beginning of Bhagavad-gītā (2.20): na hanyate hanyamāne śarīre. We are spirit soul, and therefore we are eternal. Why then should we subject ourselves to death and birth? It is intelligent to think in this way. Those who are Kṛṣṇa conscious are very intelligent because they are not interested in getting promotion to any planet where there is death, despite a long duration of life there. Rather, they want to get a body like God's. Īśvaraḥ paramaḥ kṛṣṇaḥ sac-cid-ānanda-vigrahaḥ. (Bs. 5.1) God's body is sac-cid-ānanda. Sat means "eternal," and cit means "full of knowledge." Ānanda means "full of pleasure."
As stated in our pamphlet Kṛṣṇa, the Reservoir of Pleasure, if we transfer ourselves to the spiritual world, to Kṛṣṇa's planet or to any other spiritual planet, then we will get a body similar to God's: sac-cid-ānanda—eternal, full of knowledge and full of bliss. So those who try to be Kṛṣṇa conscious have a different aim of life than those who are trying to promote themselves to the better planets in this material world. Lord Kṛṣṇa says, mūrdhny ādhāyātmanaḥ prāṇam āsthito yoga-dhāraṇām: "The perfection of yoga is to transfer oneself to the spiritual world." (BG 8.12)
The spirit soul is a minute particle within the body. We cannot see it. One practices the yoga system to raise the soul to the topmost part of the head. This practice goes on while one is living, and the perfection is reached when one can place himself on the top of the head and then break through. Then he can transfer himself to whatever higher planets he likes. That is the perfection of the yogī.
If the yogī is inquisitive to see the moon, he can say, "Ah, let me see what the moon is like. Then I shall transfer myself to higher planets," just like travelers who go to Europe, California, Canada, or other countries on earth. One can transfer oneself to many planets by this yoga system, but anywhere he goes he will find visa systems and customs systems. To go to other planets, one must be qualified.
Kṛṣṇa conscious persons are not interested in any temporary planet, even if it offers a long duration of life. If the yogī, at the time of death, can pronounce oṁ, the concise form of transcendental vibration, and at the same time mām anusmaran, remember Kṛṣṇa, Viṣṇu, he will attain perfection. The purpose of the entire yoga system is to concentrate the mind on Viṣṇu. Impersonalists imagine that they see the form of Viṣṇu, or the Lord, but those who are personalists do not imagine this—they actually see the form of the Supreme Lord. Either way, if one concentrates his mind through imagination or if one actually sees, one has to concentrate his mind on the Viṣṇu form. Mām means "unto the Supreme Lord, Viṣṇu." Anyone who leaves this body and concentrates his mind on Viṣṇu enters into the spiritual kingdom after quitting his body. Those who are actually yogīs do not desire to enter any other planet because they know that life is temporary on the temporary planets, and thus they are not interested. That is intelligence.