It is not that things exist, nor that they do not: it is simply that all phenomena are perpetually in a process of becoming. A traditional analogy for this is the form that appears from the water at the top of a fountain.
The spiritual path does not consist in seeking some escape from the world around us into some divine and eternal heaven-world. In a very real sense there is nowhere else to go; true happiness, or Enlightenment, if it is to be found anywhere, must be sought and found in the here and now.