Niels Bohr. 14 April 1928

Niels Bohr (1885-1962)

The Quantum Postulate and the Recent Development of Atomic Theory. [Offprint from Nature, v. 121, n. 3050. Edinburgh: R & R Clark, April 14, 1928].

Quarto (266 x 192mm). Fresh and unblemished in the original printed brown wrappers (very light wear, short closed tear to upper margin).

First edition, extremely rare offprint, of the paper in which Bohr stated his ‘complementarity’ principle, a ‘major advance that radically changes our whole view of the role and meaning of science. In contrast with the nineteenth-century ideal of a description of the phenomena from which every reference to their observation would be eliminated, we have the much wider and truer prospect of an account of the phenomena in which due regard is paid to the conditions under which they can actually be observed – thereby securing the full objectivity of the description' (DSB). The paper was published essentially simultaneously in German, Danish, English and French.

The published version of Heisenberg’s famous paper on the uncertainty principle (in preparation as Heisenberg and Bohr shared discussions in 1927) contains the note ‘recent investigations by Bohr have led to points of view that permit an essential deepening and refinement of the analysis of the quantum mechanical relationship attempted in this work’. The complementarity principle, that is the simultaneous use of different and contrasting or mutually exclusive concepts to describe a phenomenon (notably, for example, the wave description and the particle description of energy) ‘became the cornerstone of what was later referred to as the Copenhagen interpretation of quantum mechanics. Pauli even stated that quantum mechanics might be called ‘complementarity theory’, in an analogy with ‘relativity theory’’' (H. Kragh, Quantum Generations, 1999, pp. 209-210).

-