In the Bhagavad-gītā Kṛṣṇa says, sarvasya cāhaṁ hṛdi sanniviṣṭo: (BG 15.15) "In everyone's heart I am sitting." Hṛdi, "within the heart"; sanniviṣṭo, "I am sitting there." Sarvasya. Not only you and me, even animals insects, birds, beasts, Brahma, everyone. Sarvasya. All living entities. So sarvasya cāhaṁ hṛdi sanniviṣṭo mattaḥ: "from Me"; smṛtir jñānam apohanaṁ ca, "remembrance, knowledge and forgetfulness." Forgetfulness also. If you want to forget God, God will give you intelligence that you can forget God forever. He's so kind. Whatever you want, He will give you intelligence, "Do like this."
So there are two things. There are two living entities. One is trying to forget God, and another is trying to remember God. That's all. There are two kinds of people, or men. Men, not the animals. Animals cannot understand what is God. It is the business of human beings. So if you want to know God sincerely, seriously, then God is within yourself. He'll give you intelligence how you can know Him. But if you want to forget God, challenge God, "There is no God. God is dead," then He'll give you such intelligence that you'll always think that there is no God, that God is dead, like that. He'll give some arguments. There are so many atheists, they are also putting their arguments. So wherefrom the argument comes? It comes from God, that "You take this argument and forget God forever." Mattaḥ smṛtir jñānam apohanaṁ ca. Vedaiś ca sarvair aham eva vedyam (BG 15.15). Vedic knowledge means to understand God. That's all. One who has understood God, he has studied all Vedas. Finished. And one who has not understood God, simply studying this literature, that literature, that scripture, then he's simply wasting his time. That's all. Because (the) ultimate knowledge is God. If one cannot understand what is God after so much education, then Bhāgavata says, śrama eva hi kevalam: (SB 1.2.8) "It is simply labor, labor, waste of time." Simply waste of time. There is no education. Education, knowledge, means ultimately to understand, to know what is God. Actually; not fictitiously, vaguely. So there are many classes of men who have no understanding of God. Some of them are saying, "God is dead," or "God is impersonal," "There is no God," "Zero," "I am God," "You are God," so many things. All these people do not know what is God; therefore there are different theories. Therefore, somehow or other, if you can understand God, then your life is successful. Somehow or other. Because this human life is especially meant for understanding God. Athāto brahma jijñāsā.