From birth, people are brought up with a great deal of false indoctrination. They learn these suggestions and regard them as true. They have no qualms about building their whole lives around this supposed reality. This supposed reality consists of the supposition that everything actually exists. We are certain, for instance, that a television was assembled in a factory, whereas everything actually consists of images created inside the brain by Allah. Both the television and the factory we suppose the television was built in are merely images. We can never see their originals. All we experience are the copies in our brains. Yet we still have no doubt that this television was assembled in a factory, even though we have never seen it.  In the same way, people are absolutely sure that they themselves exist, whereas they are in fact merely an image, and that it is they themselves who are talking. They are absolutely convinced it is they who are walking. But images cannot walk or speak. Everything is shown to us, made to be heard by us or caused to be felt in the soul by Allah. Yet despite all these facts, people are still capable of believing in unreal teachings because of indoctrination.  This means that human beings are created with a predisposition to such indoctrination. This way, Allah shows us the existence of such a power of human beings.

If we were told right from childhood that everything is an image, then we would be 100% convinced of that and live our lives accordingly. If someone wishes to live according to the truth, then he or she must do so in the knowledge that everything is an image and that Allah is the only absolute being.
 
Our Lord reveals this in a verse:

Allah, there is no deity but Him, the Living, the Self-Sustaining. He is not subject to drowsiness or sleep. Everything in the heavens and the earth belongs to Him. Who can intercede with Him except by His permission? He knows what is before them and what is behind them but they cannot grasp any of His knowledge save what He wills. His Footstool encompasses the heavens and the earth and their preservation does not tire Him. He is the Most High, the Magnificent. (Surat al-Baqara, 255)