A contradiction exists between the gravitational singularity at the center of a black hole predicted by general relativity and the Pauli exclusion principle. General relativity theory asserts that collapsing stars over a certain size mass have no stable orbits and will become a gravitational singularity forming a “black hole,” having finite mass within a point sized space inside an event horizon. On the other hand, the Pauli-exclusion principle predicts that for large collapsing stars, a quark-gluon plasma will be created to form a quark star at the central core inside an event horizon. Accordingly, the exclusion principle will preclude the collapse of a star into a gravitational singularity at the center of a black hole. A number of arguments in support of the quark star as black hole... will be presented in this paper. It has been shown that the gravitational energy of a collapsed star (>3M⊙), near the core of a quark star, exceeds the energy to create a quark-gluon plasma and the deconfinement energy of quarks from the neutron. It has also been shown that, instead of a black hole, a degenerate nonstrange quark star with a maximum density of 1.1 × 1025 kg/m3 could exist at the center of an event horizon within the Schwarzschild radius. The quark star core would be an ultrarelativistic degenerate Fermi gas that is stable for masses from 3M⊙ to 20.69 × 106 M⊙. Calculations have also shown for stellar and rotating black holes that the quark star radius exists at the center and well within the radius of the Schwarzschild event horizon. However, the exclusion principle would preclude the formation of a gravitational singularity at the center. The problem for empirical science is that the quark star with an event horizon will have no emission of radiation and appear to observers to be similar to a black hole. Notwithstanding, the merger of two black holes for GW150914, producing gravitational waves, offers empirical evidence in the remnant event horizon for the existence of quark stars.