In this paper I argue in favour of a moderate and selective version of scientific realism with respect to the existence of some physical theoretical objects and the truth of some statements about them. The analysis of common sense or ordinary experience reveals that existence and truth assertions concerning familiar objects are warranted if they satisfy what we call the criteria of presence and invariance. Ordinary objects exemplify a form or a structure determined by constant and changing features with respect to the variation of the conditions of observation and a content given in sensory presence. It is claimed that some theoretical physical objects that possess a structure or a form determined by invariant and variable characteristics r...