It is no surprise then that even the stalwart pioneers of the subject remained somewhat unsettled about what exactly it all meant. Philosophers put it across by distinguishing between Ontology and Epistemology. Ontology refers to the stuff that is out there. Epistemology is how our knowledge is organised. In this sense the Newtonian advance was epistemic in nature. Ontology of what he talked about was self evident or easily verifiable. Quantum Mechanics however so puzzled its very proponents that they remained unsure what ontology there was. Little intuition could be gained over and above what the rules of calculation allowed. Was one to identify ontology with epistemy when one reached the microscopic world?