1. I am referring to Ramsey’s papers both in the 1931 and in the 1978 edition. They are:
2. Ramsey, F.P., 1931, The Foundations of Mathematics and other Logical Essays, edited by R.B. Braithwaite, Routledge and Kegan Paul, London.
3. Ramsey, F.P., 1978, Foundations: Essays in Philosophy, Logic, Mathematics and Economics, edited by D.H. Mellor, Routledge and Kegan Paul, London.
4. Achinstein, P., 1968, Concepts of Science, the Johns Hopkins Press, Baltimore.
5. Carnap, R., 1966, Philosophical Foundations of Physics, Basic Books, New York.