Einstein's relation to quantum mechanics is an example of the contradictory nature of his science: Einstein introduced light quanta or "photons" to explain photoelectricity in one of his five 1905 "miraculous year" articles, which gave him the Nobel Prize in 1922, but confessed on his death bed:
- Every Tom, Dick and Harry thinks he knows what a photon is, but they are mistaken.
- He appears to be a realist as he attempts to provide a description of the world which is independent of perception;
- he appears as idealist as he looks on concepts and theories as free inventions of the human spirit, in no way derivable from the empirically given;
- he appears as positivist as he regards his concepts and theories as justified only to the extent that they provide a logical representation of relations among sensory experiences.
- He may even, Einstein says, appear as a Platonist or Pythagorean, since his research will be guided by the aim of logical simplicity.
- Einstein’s pragmatism allowed him to feel it possible to promote the two incompatible theoretical structures simultaneously, though making the gesture of calling the photon paper a ‘heuristic point of view’ rather than a formal theory. Despite his unease about the implications for the nature of radiation, he was clear-minded enough to recognise the photon concept as an essential
part of the fundamental truth, and determined enough to continue to advocate it as
practically a lone voice for almost two decade.