 Historians of science wonder whether the ether that was loudly pushed out the front door of physics is quietly returning through the back door under the guise of “space” (Kuhn 1962, 109). Quantum field theory provides especially fertile ground for such speculation. Particles are created with the help of energy present in “vacuums”. To say that vacuums have energy and energy is convertible into mass, is to deny that vacuums are empty. Many physicists revel in the discovery that vacuums are far from empty.