When the mind detaches itself from the organ, the organ may bring any news to it, but the mind will not receive it. When it attaches itself to the organ, then alone is it possible for the mind to receive the news. Yet, even that does not complete the whole. The instruments may bring the sensation from outside, the organs may carry it inside, the mind may attach itself to the organ, and yet the perception may not be complete. One more factor is necessary; there must be a reaction within. With this reaction comes knowledge. That which is outside sends, as it were, the current of news into my brain. My mind takes it up, and presents it to the intellect, which groups it in relation to pre-received impressions and sends a current of reaction, and with that reaction comes perception. Here, then, is the will. The state of mind which reacts is called Buddhi, the intellect. Yet, even this does not complete the whole. One step more is required. Suppose here is a camera and there is a sheet of cloth, and I try to throw a picture on that sheet. What am I to do? I am to guide various rays of light through the camera to fall upon the sheet and become grouped there. Something is necessary to have the picture thrown upon, which does not move.