| | Personal Research Assistant to Sir Karl Popper, London School of Economics, 1962 - 1964 |
| | Assistant Lecturer in Philosophy, Logic and Scientific Method, London School of Economics, 1964 - 1966 |
| | Lecturer in Philosophy, Logic and Scientific Method, London School of Economics, 1966 - 1969 |
| | UK, Academic visitor, London School of Economics, 1975 - 1976 |
| | Australia, Faculty of Arts Distinguished Visitor, Department of History and Philosophy of Science, Melbourne University, 1976 |
| | Australia, Visiting Professor, Department of History and Philosophy of Science, Melbourne University, 1985 |
| | USA, Visiting Professor, Center for Study of Science in Society, Virginia Polytechnic and State University, 1986 |
| | USA, Visiting Professor, Department of Philosophy, Virginia Polytechnic and State University, 1987 |
| | USA, Visiting Professor, Minnesota Center for Philosophy of Science, University of Minnesota, 1987 |
| | UK, Lakatos Visiting Fellow, London School of Economics, 1987 |
| | Australia, Visiting Fellow, London School of Economics, 1987 |
| | Australia, Visiting Fellow, Philosophy Program, Research School of Social Sciences, Australian National University, 1995 |
| | USA, International Fellow, Center for the Study of Science in Society, Virginia Polytechnic and State University, 1995 |
