This volume constitutes the Proceedings and Discussions of the 1968 Salzburg Colloquium in the Philosophy of Science. The Colloquium was held at the Institut fUr Wissenschaftstheorie of the Internationales Forschungszentrum fUr Grundfragen der Wissenschaften, Salzburg, Austria, from August 28 to August 31, 1968, under the joint auspices of the Division of Logic, Methodology and Philosophy of Science of the International Union of History and Philosophy of Science, and the Institut fur Wissenschaftstheorie of the Internationales Forschungs zentrum, Salzburg. The Colloquium was organized by an executive committee consisting ofY. Bar-Hillel (President), M. Black, J. Hintikka, B. Juhos, M. Strauss, and P. Weingartner (Secretary). The Colloquium was generously subsidised by the International Union of History and Philosophy of Science, and by the Internationales For schungszentrum, Salzburg. The Colloquium was divided into three main sections: Induction and Probability (Chairman: 1. Hintikka), Foundations of Physics (Chairman: M. Strauss), and Science and Ethics: The Moral Responsibility of the Scientist (Chairman: M. Black). This volume contains all papers presented at the Colloquium. Six of those papers concerning Induction and Probability, have, with slight changes, already been published in Synthese 20, 1969. Although the articles of the section Science and Ethics were only read at the International Congress of Philosophy in Vienna on September 3, 1968, the discussion on them took place in Salzburg two days ago. This was possible, because early drafts of all papers had been sent to each participant, in order to prepare appropriate discussions.