Do elementary particles describing gravity exist, represented as large quantities of undiscovered gravitons? Does dark matter exist, or is it perhaps the graviton that physicists are looking for? Does dark energy exist, and what are the conclusions of Hubble’s observations? Is “uncertainty” a physical phenomenon or is there a deeper cause of uncertainty? Is light made up of particles or is it a wave or is it both? Is spacetime a physical reality or is it just a combination of space and time?