1. 1. The basic references are R. Carnap and Y. Bar-Hillel, An Outline of a Theory of Semantic Information, Technical Report No. 247, M.I.T., Research Laboratory of Electronics, 1950; reprinted in Y. Bar-Hillel, Language and Information, Addison-Wesley, Reading, Mass., 1964, pp. 221-274; and Y. Bar-Hillel and R. Carnap, 'Semantic Information', British Journal for the Philosophy of Science
2. 2. 4(1953) 147-157. (Slightly different version also in Communication Theory: Papers Read at a Symposium on Applications of Communication Theory [ed. by W. Jackson], London 1953, pp. 503-511.)
3. Cf. my paper ‘On Semantic Information’ in the present volume (forthcoming in Physics, Logic, and History [ed. by W. Yourgrau], The Plenum Press, New York 1970), last few pages.
4. Karl R. Popper, Logik der Forschung, Springer-Verlag, Vienna, 1934. (English translation, with additions, as Logic of Scientific Discovery, Hutchinson’s, London, 1959.)
5. See my paper. ‘The Varieties of Information and Scientific Explanation’, in Logic, Methodology and Philosophy of Science III, Proceedings of the 1967 International Congress (ed. by B. van Rootselaar and J. F. Staal ), North-Holland Publishing Company, Amsterdam, 1968, pp. 151–171.