The energy density of the false vacuum can be attributed entirely to the Higgs fields. Furthermore, as can be seen in figure 3.5, any deviation of the Higgs fields from their false-vacuum values would require an increase in energy density. This implies that the false vacuum has a peculiar property which distinguishes it from all familiar materials: when the volume of a region of false vacuum is increased, the energy density cannot decrease, but instead remains at a constant value.