78 SOCIAL SCIENTIST mechanics, where the former had an inclination towards positivism while the latter moved towards realism. There were continued discussions of a similar type between Bohr and Einstein over a long period, even after the establishment of quantum mechanics. After the stage of phenomenology one enters a stage of discovering the substance of the new stratum which underlies the new phenomena, and then the next stage of disclosing the rules which govern the new stratum. Mituo Taketani named the former the substantialistic stage and the latter the essentialistic stage. His theory claims that the cognition of nature is a dialectic-philosophical process which advances in a spiral form—and each cycle in the spiral is composed of three stages phenomenological, substantialistic, and essentialistic. His theory has for its basis the dialectics of nature, namely, the strata-structure of nature itself. If one takes an example from quantum physics, the discoveries of regularities in the atomic spectra aie regarded as belonging to the phenomenological stage. Establishment of the atomic model of Rutherford and the development of the early quantum theory of Bohr correspond to the substantialistic stage. Then came the completion of quantum mechanics which is the essentialistic stage. It should be pointed out here that one always finds in the essentialistic theory new traces of a phenomenological character which prepare for future development into deeper strata of nature. 1 VI Lenin, Materialism and Empiric-Criticism, Progress Publishers, Moscow 1967. 2 Gerald Holton, ^The Metaphor of Space Time Events in Science", Ernos-Jahrbuch XXXIV, 1965. 8 P Langevin, International Conference on New Theories in Physics, held in Warsaw, 1938. 4 B d^Espagnat, Conceptual Foundations of Quantum Mechanics, Ch 17, W A Benjamin Inc. California, 1971. 5 W Heisenberg: 'From a Life of Physics5, International Atomic Energy Agency Vienna, 1968. 0 Shoichi Sakata, My Classics-Engles ^Dialektik der Natur9 Supplement of ThejProgress of Theoretical Physics, No 50, 1971. 7 Shoichi Sakata, Theoretical Physics and Dialectics of .Nature, in Supplement of The Progress of Theoretical Physics, No 50, 1971. 8 Shoichi Sakata, On the Interpretation of Quantum Mechanics, in ibid. 9 Shoichi Sakata, Theory of Elementary Particles and Philosophy, in ibid. 10 Mituo Taketani, Dialectics of Nature'on Quantum Mechanics, in ibid. 11 Mituo Taketani, Observation Problem of Quantum Mechanics, in ibid* 12 Shoichi Sakata, Philosophy and Methodology of Present'Day Science, in ibid.