Abstract

“Bohr was primarily a philosopher, not a physicist, but he understood that natural philosophy... carries weight only if its every detail can be subjected to the... test of experiment”. As a result his approach differed from that of the school-philosophers whom he regarded with a somewhat “sceptical attitude, to say the least” and whose lack of interest in “the important viewpoint which had emerged during the development of atomic physics” he noticed with regret. But it also differed, and to a considerable degree, from the spirit of what Professor T. S. Kuhn has called a “normal science.” Looking at Bohr's method of research we see that technical problems, however remote, are always related to a philosophical point of view; they are never treated as “tiny puzzles” whose solution is valuable in itself, even if one has not the faintest idea what it means, and where it leads: “For me” Bohr writes to Sommerfeld in 1922 “[the quantum theory] is not a matter for petty didactic details, but a serious attempt to reach... an inner coherence.” Emphasis is put on matters of principle and minor discrepancies, or “puzzles” in the sense of Kuhn, instead of being deemphasized, and assimilated to the older paradigm, are turned into fundamental difficulties by looking at them from a new direction, and by testing their background “in its furthest consequences by exaggeration”. A noteworthy example of Bohr's “non-normal” and rather metaphysical approach to physics is his scepticism in the face of the success of his own atomic model.