If you have no sufficient knowledge on a subject matter and if you want to enlighten others with your speaking, that is cheating. Because you have no sufficient knowledge, why you are speaking to others? That is cheating. He is posing that, "I know," but he does not know. This is cheating. Imperfectness of senses. They are declaring that "We are studying the planetary system by," what is called, "telescope." But who has manufactured this telescope? You have manufactured, or your brother has manufactured. But he has got imperfect senses. How the telescope will be perfect?
So this is going on. They are simply cheating public. They have no sufficient knowledge, still they are trying to speak of some subject of which they have no sufficient knowledge. Besides that, the scientist . . . one scientist proposes, theorizes something today, and another scientist makes this proposition, this theory, null and void and he speaks something else. That is also due to the imperfect of senses.
So that is called mistake or illusion. Mistake means calculation, mathematical calculation, "Two plus two equal to four"; but sometimes by mistake we may put "three" or "five." That is called mistake. And illusion, to accept something for something. Just like we are accepting, when somebody inquires, "Who are you?" you just give identification of your body: "I am such and such. I am an American. I am born of such father and mother, by a . . ." But this body is not yourself. You are spirit soul. Therefore it is called illusion. And because we are struggling on the platform of illusion, there is mistake, there is cheating, and the senses are imperfect. This is the position.
Therefore, the so-called modern scientific world, advanced, they do not know what is the actual living force within this body which is moving this body. So long the soul or the living force is within this body, it is moving. As soon as the spirit soul is out of the body, it is . . . we call it is dead.
So we have got medical science for this body, we have got psychology for the mind—everything we've got—but where is the science of the soul, which is moving the body and the mind? Where is that science? Is there any such science? You are all students, I think. To understand what is the basic principle of moving this body and the mind, is there any department of knowledge in the universities all over the world to understand this science? Is there any?
Then where is your knowledge? Somebody is accepting the mind as the self, and somebody is accepting the . . . this gross body as the self. They do not know that both the body and the mind, both of them are material. And the force, or the entity, which is moving this body and mind, that is spirit. So they have no knowledge.
So that knowledge is being imparted by the Supreme Personality of Godhead, dehino 'smin yathā dehe (BG 2.13). Dehī, the soul, the proprietor of the body . . . just like you are the proprietor of your body. When I touch your finger, if I ask even a small child, "What is this?" he will immediately say: "My finger." He'll never say: "I finger." "My finger." Just try to understand. When any part of your body I touch, if I ask, "What is this?" you will say: "This is my hand," "This is my leg," "This is my nose," "This is my . . ." Everywhere you will say: "my." But nobody knows what is that "I." Nobody knows.