Local realism is a philosophical concept in physics that suggests objects have definite properties and exist independently of observation. It posits that information about an object is determined by its local environment and that influences cannot travel faster than the speed of light, adhering to the principles of Einstein's theory of relativity. In local realism, the behavior of particles is predictable and can be explained by local interactions. This view contrasts with the implications of quantum mechanics, where particles can exhibit entanglement, leading to correlations that seem to defy local realism by suggesting that distant particles can instantaneously affect one another.