He knows it because when he looks at any being, he looks at him thinking, "This is I," and as he knows about himself, so he knows all about every being. In the physical existence we see so many different forms, but behind this physical existence there are not many lives, but one life. By living in this one life, in this one God, he knows every being and thing. There is God in the thing also, in the plant; only in the plant He has not opened His eyes.