Does the following conjecture make any sense? Any universe that exists must contain fields of one kind or another - a universe which contains no matter or energy will still contain fields, but they can be perfectly flat, except: If the uncertainty principle holds in all possible universes, then there can be no fields in any universe that are perfectly flat on the quantum scale, and any deviations from perfect flatness will manifest as particles of some kind. So if the uncertainty principle holds in all possible universes, then all universes must contain particles. Only if the uncertainty principle does not hold in all possible universes can any universe contain nothing other than perfectly flat fields. Are fields mandatory in all possible universes, and does the uncertainty principle hold in all possible universes?