1. See, e.g., the works of Ernst Mach, Heinrich Hertz, Pierre Duhem and Henri Poincar�.
2. Karl Popper, ?The Demarcation between Science and Metaphysics?, in Conjectures and Refutations, Routledge, 1963, pp. 253 ff.
3. See, e.g., Karl Popper, ?The Nature of Philosophical Problems and Their Roots in Science, The British Journal for the Philosophy of Science 3, 124; A. G. Van Melsen, From Atomos to Atom, Duquesne University Press, Pittsburg, 1952; Ernst Cassirer, Determinism and Indeterminism in Modern Physics, Yale University Press, New Haven, 1956; J. W. N. Watkins, ?Between Analytic and Empirical?, Philosophy 32 (1957);
4. J. W. N. Watkins, ?The Haunted Universe?, The Listener, November 21 and 28, 1957; J. W. N. Watkins, ?Confirmable and Influential Metaphysics?, Mind 67 (1958);
5. S. K�rner, Colston Symposium on Observation and Interpretation, Butterworth, 1957, p. 97; P. Feyerabend, ?An Attempt at a Realistic Interpretation of Experience?, Proc. Arist. Soc. 1957?1958, and ?Complementarity?, Arist. Soc. Supp. 32 (1958); and various works by A. Koyr�, M. Jammer, H. Butterfield, G. Sarton, G. di Santillana, and E. A. Burtt.