66 COMMUNICATION atomic spectra, the several spectroscopic effects, the theory of absorption and emission of radiation were some of the areas where quantum mechanics' was found essentially correct by experimental verification. Hence the 'wave-particle duality5 must be accepted as part of the rational core of the theory* The probability interpretation of ^ marks a sharp break with the mechanistic determinism of classical physics and is a concrete expression of the statistical nature of quantum phenomena. This interpretation, though not directly verifiable, has not run counter to experimental work and data, and, in fact, has been upheld by the work on spectra. This must also be considered a part of the rational core of quantum theory. The idealist interpretation of quantum mechanics is based on the acceptance of two main principles, the Hcisenberg Uncertainty Principle and the Complementarity Principle. The two cannot be considered in isolation, since, as will be shown later, in essence the latter is only a stronger and more explicit denial of objective reality than the former. The Uncertainty Principle states that a simultaneously precise specification of both position and momentum is not possible.This is expressed quantitatively as AX. Ap> j-—, where AX, Ap are the uncertainties in position x and momentum p and h is Planck's constant. In other words, the product of the uncertainties in co-ordinate and momentum is greater than or equal to j—. Two points must be clarified about the role of the un-certainty relation. Feibles on Both Sides First, a relation expressing the coarseness of measurement cannot be elevated into a principle denying the possibility of the existence of specific values of position and momentum. To deny the existence of such specific values for position and momentum means that we are not permitted to talk of a trajectory and this leads to a denial of objective reality. There is also the implicit statement that there do not exist precise values of position and momentum without measurement. This is an idealist position denying the existence of objectively real values of position, momentum and other quantities. The Heisenberg Uncertainty Principle must be understood merely as a relation expressing the coarseness of the microscope method of measurement (from a study of which the Uncertainty Principle is derived) and not as a rigid 'law of nature'. Fock, a Soviet physicist, is one of the scientists who accept this understanding of the uncertainty relation.1 Secondly, one cannot say that the microscope method of measure* ment is the only possible method of measurement and hence the uncertainty holds for all time. In fact, the Soviet; physicist, A A Sokolov, hasr pointed out a method where "the electron reveals itself without the intervention of an observer using instruments possessing microstructure ta detect it/'2 The electron, moving with high energy in a synchrotron^