The world does not HAVE to exist, but if it does the only condition is that it is imperfect. There is non-existence, which is nothing, the time before the big bang.
And there is 'heaven' which is perfection and there is no suffering because everything is perfect.. but this is not existence.. because existence requires dis-unity.. which incidently is imperfection.. and subjectivity. Subjectivity, or seperation from the 'self' is required for you to 'see' the world.. otherwise you are whole and what is there to see, you cannot see yourself etc. (this is heaven)
I know this looks bad...
