Analytical study of this material world, they are not sufficient by themselves. You have to find out the spiritual power behind it. So sannyāsa means, generally, the sannyāsa, those who have taken up the renounced order of life, they search after the Supreme Truth and make an analytical study of this material world. That is called sāṅkhya-yoga.
Kṛṣṇa says, sāṅkhya-yoga . . . sāṅkhya and yoga. And yoga means direct connection with the Lord. Direct connection with the Lord. Just like in the darkness. In dark, in the darkness, you cannot see anything. Suppose your room is closed and dark. You cannot see anything. But when you come to the light, you come to the sunlight, then you can see yourself and everything very nicely. So yoga, this word yoga, means to come in direct touch with the absolute light or Absolute Truth. That is called yoga.
So by analytical, analytical study of this material world, that is not sufficient. Unless you come in direct touch with the Supreme Absolute Truth, this knowledge has no value. This knowledge has no value. If you want, you can study anything, any straw in the street. You can make a very analytical study of the straw. But that sort of knowledge has no value unless you come to the point of our spiritual existence.
So sāṅkh . . . so Kṛṣṇa says . . . the idea of sāṅkhya-yoga, analytical study of this material world, means you have to find out the spiritual existence. And that spiritual existence you can have when you directly come to the spiritual life. So direct process is Kṛṣṇa consciousness. Kṛṣṇa is just like the sun.