Now they have made so much scientific improvement, material scientific improvement. Now, suppose there is a body, dead body. Now, if the living force was something material, then bring something material and inject in that dead body and get him up again. No, that is not possible, because that spiritual thing is gone, and we have no control over the spiritual matt . . . spiritual thing. The spirit soul, that is a superior nature. We have been simply informed in Bhagavad-gītā, that is a superior nature. This is inferior nature. So this inferior nature is my bondage. I am not this inferior nature.
So Kṛṣṇa says, na hi jñānena sadṛśaṁ pavitram iha (BG 4.38). So as soon as we become, I mean to say, revived to our position, brahma-bhūtaḥ, then our first symptom will be prasannātmā. Prasannātmā—we shall be joyful. Prasannātmā na śocati na kāṅkṣati. (BG 18.54)
There will be no lamentation and no hankering. But the difficulty is that even if we rise up to the brahma-bhūtaḥ stage and if we do not take to the service of Kṛṣṇa, then there is possibility of falling down again. That information we have got. Āruhya kṛcchreṇa paraṁ padaṁ tataḥ patanty adhaḥ anādṛta-yuṣmad-aṅghrayaḥ (SB 10.2.32).
Just like you may rise very high in the sky, but if you have no shelter there, if your aeroplane or Sputnik fails, then you again you fall down. Again you fall down. So if you rise up to that stage that you can attain some planet and take your rest there, so then there is no possibility of falling down. But so long you are in the sky, oh, there is every chance of falling down, every chance.
Similarly, simple understanding of brahma-bhūtaḥ stage will not help me unless I take shelter unto Kṛṣṇa. As soon as I get shelter unto Kṛṣṇa, as soon as I engage myself in the service of Kṛṣṇa, then there is no chance of falling down again into this material world. Because there is engagement. Our nature is such that we want some engagement. Paraṁ dṛṣṭvā nivartate (BG 2.59).
Just like a child. Child is playing all day and doing mischief in the house, and . . . so he cannot be stopped mischief-doing. He must be given some engagement. If he's given some engagement, some playthings, and if his attention is diverted there, then he'll stop mischief-making in the house. Otherwise, idle brain, devil's workshop. He will go on, go on.
So therefore we must have spiritual engagement. Simple understanding that, "I am spirit soul" will not help me. Brahma-bhūtaḥ prasannātmā (BG 18.54). The brahma-bhūtaḥ stage, situation, is that, "I am not matter, I am spirit." That's all right. But we have to sustain the spirit. How you can sustain? You can sustain when there is spiritual engagement. Otherwise, it is not possible. Otherwise, I may continue for some time, but there is chance of falling down. Because we have got this information and a practical experience also great, great, I mean to say, yogīs and jñānīs, they again come.