All particles with 1/2 spin (or 3/2 spin) are called fermions, and obey Fermi-Dirac statistics. This means that no two fermions can be in the same point in space at the same time. This is not true for the other type of subatomic particle, called a boson. More than one boson—like a photon—can exist in the same point in space at the same time. 