If an economist or an economic historian speaks about ethical or moral problems, one should be suspicious. Karl Popper continually repeated that he did not want to preach, and I believe that his deep-rooted distrust of modern philosophical moralists, who usually preach water and drink cognac, led to his not writing a greater work on ethics. Nevertheless he was a moral person, and perhaps we can learn more about his cosmology, his methodology, and about his philosophy in general if we probe into some of the ethical foundations of his life and his thinking. It may become apparent to you that I do not refer primarily to Popper's Open Society and Its Enemies or other works of his political writings alone. In choosing not to do so, it is my intention to demonstrate that all his thinking is deeply rooted in ethics.

Since studying at the London School of Economics and Political Science in 1967–1968 the question of the ethical roots or moral sources of Popper's philosophy has never ceased to occupy my mind. It was too obvious that this man and scientist was a human being in the purest sense. In those revolutionary days, Sir Karl's most important book, The Logic of Scientific Discovery, was abbreviated LSD, which is also the abbreviation of Lysergic Acid Diethylamide, a potent synthetic hallucinogenic drug.