The mirage has no reality other then its substance from which it is made of

In the realm of truth there are no external objects, but that the waking (mind or universe)  is mere mirage created out of the soul or  consciousness, the innermost self. The mirage has no reality other then its substance from which it is made of.  To understand this, one must know the nature of the  dream.

There is nothing external to Mind. Mind has got everything in itself as in dream. In dream one has external objects, but they are not separate from mind when one examines them after awakening to realize the fact that the dream was mere a mirage.

The word dream is generally used with reference to the physical body, for it means "my dream" which occurs within my body. One’s body reappears in dream, he dreams a journey, but he does not actually perform it, his body seems to do it.

People, who stamped their foot on the ground to refute to show the world is real, ignore that in dream they would do exactly the same--stamp their dream foot on the ground and assert it to be real. 

The three states are known in the waking state, not in dream or sleep. Hence one must detach himself from them whilst awake, if he is to realize Atman. In the waking experience alone one get s the knowledge of Atman. The mind has to be so sharp in order to grasp the formless substance and witness of the three states; he will know the true self is Atman not the ‘I’.

Deep sleep is followed by dream and waking, it is called the seed or causal state: otherwise if it continued unbroken it would be called Atman. It is a state, something which comes and goes; the objects of each state are included with it. The Gnani detaches himself from them, sees them coming and going, and thus remains in the ever-present non-dual Atman(soul or consciousness).