The soul is migrating, transmigrating. There are 8,400,000 species of bodies; and you are transmigrating from one to another, another, another, in this way. They don't care for it. Even if you are Hindu... [break] ...he is informed, that if you are acting like this you are going to be a tree next life, "Oh, it doesn't matter, let me enjoy." You see. They say frankly, "If I become tree what is the harm? I shall forget." The people have become so rubbish that they have lost their self-interest.
Just like if you say to a child that "You are always playing, you are not going to school, you are not becoming educated, you will suffer in your future life, you will have no position in the society." But if he says, "I do not care..." He may say that, but the risk is there. Similarly the modern human being, you inform him about the transmigration of the soul, and by his activities he is supposed to become next life very low grade animal, or aquatics, or reptiles. So if they are informed, if they do not care, that is not very good intelligence. This is a fact.
Prabhupada's lecture - Śrīmad-Bhāgavatam 1.2.8 - New Vrindaban, September 6, 1972