Mahat, this mahat-tattva, total material energy. So one can understand by taking lesson from different varieties of living entities coming out of this material nature. Just like there is one earth, but different varieties of plants are coming out, even without our endeavor.
Of course, in our garden we take care of sowing different types of seeds, but in a jungle you can go and see there are varieties of plants and trees; they are coming out of the earth and they are producing different varieties of fruits and flowers. So, "The variety is the mother of enjoyment." You cannot make it impersonal. Variety means each and every thing is a personal, individual being. That is variety.
As Kṛṣṇa has already explained, puṇyo gandhaḥ pṛthivyāṁ ca (BG 7.9). There are reservoir of different flavor within the earth, but according to the bīja, they are coming out differently. There is rose scent, there is lotus scent, there are varieties of scent—they are already within the earth. But our materialistic scientist, they cannot take out any flavor from the earth. They have to take the flavor from the flowers, not from the earth.