The fundamental questions that we wish Prof. The realist regards science as a way of increasing our knowledge about the world, and eventually hopes that it might lead us to discover the entities of which the world is made and the laws they obey.
Realism is, in a sense, the natural or pre-philosophical point of view.
Performing an experiment and opening a door are not essentially different. Maxwell's laws can be confirmed by experiment just as can the existence of atoms, or the curvature of the earth. Positivism is the sceptical response to realism. Tomorrow they will have been replaced by something utterly different. Examples of many curves fitting a few data points often crop up here.