People are after knowledge. So many there are, departments of knowledge. But according to Bhagavad-gītā, real knowledge is to understand the soul, the Supersoul and the material world. So He's analyzing these material elements: mahā-bhūtāny ahaṅkāraḥ. Mahā-bhūtāni. There are five gross elements, which are called mahā-bhūtāni, great material elements. And what are those?
(reads commentary) Khadiny ahaṅkāras tad-hetus tamaso bhūtadi-saṁjṣo buddhis tad-hetur . . . pradhāno mahān avyaktaṁ tad-hetus tri-guṇavasthaṁ pradhāna indriyāṇi śrotrādīni, one after another.
This sky and false ego is due to the intelligence. Everything begins from the subtle. The most subtle element is the spirit soul, and little grosser than the spirit soul is the intelligence. And little grosser than the intelligence is the false ego, identification. And little grosser than the false . . . intelligence, is the mind. And from mind, then the senses. And the senses, next the grosser element is the body. So we have to analyze according to the śāstra, because it is not possible . . . suppose the modern scientist is given to find out where is the soul in this body. It is not possible.
So we may be very proud of advancement of knowledge, but actually we are not yet advanced, so far material science is concerned, to understand the basic principle of the moving force which is moving this body, the . . . on account of the presence of the soul, we have got so much intelligence, we have got so much thoughtful, psychological effect. So many things wonderful they are. But as soon as the soul is not there, everything collapse.