“…But we should confess that this guideline is still unclear and weak today. 43 Ten years later, on April 4, 1923, in a speech at the inaugural session of the first Congress of Polish Physicists and Chemists in Warsaw, bearing in mind a) the non-existence of a unified theory of optical phenomena and b) the existence of a contradiction in the descriptions of optical phenomena offered by wave optics and the (new) quantum optics, Natanson saw serious limitations of the so far postulated hypothetical entities of theories: So let us not believe in the existence of correct and simple waves; let us also refuse to trust in the objective existence of quantum atoms. The incompatibility of undulation and quantum Optics only testifies to the fact that both disciplines, having picked up a thin thread of similarity in the phenomena, extended it, each its own, beyond their proper scope.…”