A journey of religion prepares a person for a much higher journey of the Bliss or the journey of the Dharm.

This great journey of Dharm is all about realization of the Bliss.

And an illusion of something is a state of mind when one experiences it as if it is true. However, in reality, truth does not exist as it seems to be real in the illusion.

There is a famous story of the snake and the rope. One can take a rope to be a snake or one can take a snake to be a rope. One can find numerous examples of both in history or in life.

However, when we say there might be some or the other illusion in one's life, this statement is in itself a truth.

The other characteristic about illusion is that it is temporary. At one or the other point of time an illusion is bound to vanish. For some people, illusion may be a momentary thing, and for some others it may last longer.

Thus illusion is directly related to the time. Illusion is always for the time being. And, after the expiry of the time, the illusion, which we take to be real, vanishes.

In other way whatever vanishes after a time is illusion.

Now let us take truth. This truth is also true for the time being. Let us take the example of life. It exists, and it is true, but only for a certain period of time. It is not a truth that is eternal.

Therefore, in philosophy, this truth, or the truth of physical world is real or true, but only for the time being. After the expiry of this time, this physical world which we perceive, is bound to vanish.

In this way, even truth is a temporary phenomena, which vanishes after a time.

Now, we know, what vanishes is illusion, and therefore truths of physical world finally, prove to be an illusion.

Thus truth of the physical world is an illusion in itself, because it is true only for the time being, not eternally.

That is why, when we start the great journey of the Dharm, we always keep in mind that truth of the physical world is also and illusion, and it is not The Truth, the Eternal Truth, The Absolute Truth and so on.

In the journey of Dharm, we try to seek The Truth, so that the Bliss, which we start realizing in this life, may continue eternally. We are primarily interested in a truth that is eternal.

This does not mean that we should ignore truths of the physical world. This truth of the physical world, in fact, serves the basic purpose of realizing the Bliss, because these are the means to our end. If life itself is ignored, then what is left there to attain?