Realism is a pillar of science along others (science as economy of experience etc). However it has been doubted as the unquestioned one recently.
Here are some of the possible strong cases for the argument
**Most knowledge growth in science has come from endorsing realist, objectivism, endorsing real world events, properties, microstructures. Such advance would not be explained if the objects and predicates referred to real world phenomena (Norris)
**inference from best explanation, a realist stance, stands strong in theory selection
**theories that originated from realist perceptions have solved otherwise mysterious phenomena (quantum phenomena like chrmical bonding) thus the realist attitude toward this theories overpowers others (Bhom)