The phenomenal world -- consisting exclusively of composite "things" -- is in constant flux. This transiency is, paradoxically, its only steady characteristic.
There is a beyond, which is utterly different and incomprehensible to a mind that has only known and taken this flux to be real. This "beyond" goes even beyond beyond and is called nirvana. It is peaceful and blissful. The shore we are on is called the "continued wandering on" (samsara). It is restless, painful, and impersonal.
It used to be that western minds, given to philosophizing about ideas rather than direct mystical experience, called the distinction phenomenal and noumenal. But this carries many connotations and assumptions that do not apply.
Words will never suffice. The words themselves have no meaning. And although we understand today, it is not because of the words that mark it. Those same words mean nothing to the person who does not understand it. Understanding transcends words.
Kwan Yin beheld from on high and saw that all conditional things are empty (impersonal). By "things" she meant those things closest to us -- our bodies, feeling, perceptions, volitions, and consciousness. Seeing them as they really are -- passing, unpleasant, and impersonal -- her heart was utterly freed by non-clinging (am P H O T O/flickr).
Why would we ever want to leave this pleasurable transient, unsatisfactory, impersonal world? There's pleasure here. It's true. There is. There's a greater peace, a greater bliss there, but we would have to renounce the lower for the higher, and few of us are will to lose a bird in the hand for more in the bush.
We want them both. It's the nature of experience here, marred as it is with greediness for what we like, aversion to what we do not, and confusion about neutral things we see neither value nor harm in.
Wise reflection on this impermanent aspect of the illusion here is liberating. But it may be unpleasant if we take it personally. If we view it mindfully, there is no pain and nothing personal about it. Viewing it in this way is liberating. "Not having been, they [things] come into being. But once having been, they cease." Why would we ever become attached if we directly knew that?
Passing, passing, passing. Nothing to grasp. Falling away, falling away, falling away, their dissolution is bliss because their coming together is unsatisfactory. We want it to be one way over an other. Far better it is to escape to reality.