Niels Bohr, “Das Quantenpostulat und die neurere Entwicklung der Atomistik”, in Die Naturwissenschaften, volume 16, part 15, 13 April 1928, pp 245-255 in the issue of pp 245-268. This is the complete weekly issue, without the wrappers, removed from a larger bound volume. Very Good condition.  $500

”From the epistemological point of view, the discovery of the new type of logical relationship that complementarity represents is 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 now 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, since the description is based on purey physical operations intelligible and verifiable by all observers. The role of the classical concepts in this description is obviously essential, since those concepts are the only ones adapted to our capabilities of observation and unambiguous communication.