A radical proposal for the cosmological constant problem*

If our universe has a large cosmological constant, would we necessarily know? The obvious answer depends on an assumption of homogeneity, which may fail at the Planck scale if Λ comes from quantum fluctuations. I show that a large set of initial data describe a universe with small average expansion even with an enormous cosmological constant. Questions about time evolution remain, but it is possible that a large Λ can produce Planck scale "spacetime foam" while remaining hidden macroscopically.