Sir Karl Raimund Popper: In Memoriam

Originally published in Intellectus 31 (Jul-Sep 1994), pp. 1-3.
Intellectus is the official bulletin of the Hong Kong Institute of Economic Science (IES).
(HTML Version: 29th January 1997)

"Every time a man dies, a whole world dies with him." -- Josef Popper-Lynkeus

If one is to name a thinker who has had the greatest influence on IES in its intellectual foundation and pursuit, that thinker is, without any doubt, Sir Karl Popper. Indeed, for quite a number of IES core and founding members, his teachings have become part of their intellectual second nature. To our great sorrow, on Saturday, 17th September 1994, Sir Karl passed away at the age of 92. In view of his immense intellectual influence, it is no exaggeration to say that with his death, a whole world dies with him. But the passing away of a great man of ideas should not simply be the end of an era. It should and can be a galvanising event that propels the Popperian tradition to new heights.

Sir Karl's contribution to 20th Century Western thought had been great and manifold. His view of science, first propounded in his Logik der Forschung in 1934 (later translated as The Logic of Scientific Discovery in 1959), revolutionised the whole idea of what constitutes growth in science. Prior to this publication, many philosophers and scientists since Francis Bacon believed that scientific knowledge was based upon a large corpus of confirming evidence. The truth of statements about these evidence, in their opinion, was then transmitted through inductive inference to render support for a theory. While David Hume and others had expressed scepticism about whether the transmission of truth from observational statements to theory through induction is adequate justification for science, none had proposed a more powerful alternative. Similarly, Kant's ingenious idea of the synthetic a priori left unsolved the following insurmountable problem. Admittedly, one can endorse the idea in principle that, in order for experience to be possible at all in the first place, there must be some conceptions by which the human mind uses to filter and organise experience. Hence these conceptions themselves cannot be derived from experience. Rather, they are logically prior to experience. However, to accept this point in principle does not amount to agreeing on what exactly is the content and scope of such synthetic a priori conceptions. Once we step beyond such barest minimum as space and time, how are we to know the content and scope of all the synthetic a priori conceptions which the mind must have brought to bear upon experience? Even the hope to construct a universal grammar remains elusive.

Popper's invaluable contribution in this area consists in his successful attempt to confront Hume's scepticism, while extracting from Kant the idea that the concepts we use are not determined by experience but supplied by our creative mind. His success is due to his full understanding of the limitation of induction and his subsequent reliance on a property of deductive logic, namely, the re-transmission of falsity. In a deductive inference, we infer from premises of general statements to conclusions about particular instances. Falsity of the conclusion then reflects falsity of at least one of the premises. Arguing against the reliance on induction, Popper always emphasised that 1000 confirmations of a theory still cannot guarantee its confirmation in the 1001st instance. Newton's Law of Gravitation, for example, had dominated the world of physics for 200 odd years, and could therefore be safely regarded as being universally true. However, it was eventually replaced, in the early 20th Century, by the more acceptable theory advanced by Einstein. Popper came to the conclusion that even science, which we used to think of as being an established and unerring branch of knowledge, is after all fallible, because in actual fact scientific theories are only hypotheses, and may be falsified and replaced one day. Accordingly, what is important in science is not the confirmation, but the attempted falsification, of theories. The working scientist should not be easily satisfied with his theories' being confirmed by experiments. On the contrary, he should always exercise his creativity to work out the multifaceted ramifications of these theories and test their implications in as many different types of situation as possible. In this connection, he should seek ways to discover where errors may occur. This critical attitude enables him to know the shortcomings of his theories, and therefore understand them better. He should then strive to propose better ones, thereby opening the way to scientific progress.

Popper labelled his philosophy "critical rationalism" and later, "evolutionary epistemology", because he regarded the growth of human knowledge, just like that of animals, as a constant process of evolution and refinement. Theories which can withstand the scientist's severest attempted refutations will survive and become preserved (for the time being); those that he falsifies will be replaced. This, then, is Darwin's idea of "the survival of the fittest", but on an epistemological dimension: we retain those scientific theories that survive our severest and most critical tests--tests not aimed to confirm, but to falsify, their truth.

An important application of critical rationalism is in politics. Popper's contribution, in the context of previous political theories, lies in a problem shift from the question "Who should rule?" to the question "What institutional arrangement can best prevent abuses?". It was prompted by his insight that it is easier for a people to agree on what known evils are to be removed or avoided than to agree on what good is to be achieved. A significant implication of his political philosophy is that, the politician, like the scientist, should always be aware of his own fallibility and therefore constantly look out for erring policies. For Popper, a good politician is one who is critical of his own political judgments and programmes and shows willingness to correct them when they prove to be erroneous. Should he fail to correct them, he must then have the honesty and moral courage to admit his shortcomings. Similarly, political parties should have the incentive to borrow from and execute any good ideas of their political competitor. In The Open Society and Its Enemies (1945), Popper criticised in the most scathing manner Plato, Aristotle, Hegel, and Marx for claiming to possess infallible knowledge and even recommending dictatorship and totalitarian government as means to put such knowledge into practice. This two-volume book made a strong impact on the Western world. Not only did it help Popper gain international recognition but it also strengthened many people's conviction that an open and reasonably democratic society is by far the best possible society that can minimise the undesirable effects of Man's fallibility. Together with his friend, the late F. A. von Hayek, Popper is perhaps the best known critic of Marx in the 20th Century. And in The Poverty of Historicism (1957), he demolished the intellectual foundation behind the central tenets of Hegel, Marx, and other totalitarian thinkers.

Apart from shedding light on the logic of scientific discovery and on the desirability of the open society, Popper had also enlightened and influenced leading thinkers in many other fields. Always a staunch opponent to the compartmentalization of knowledge, he worked incessantly on a wide range of disciplines. Indeed, his universe of learning was an open one. In his early years, he speculated on the rise of Western polyphonic music as well as on entropy and the arrow of time. To counter the domination of the interpretation of quantum physics by the Copenhagen School, with its regrettable emphases on the subjectivist understanding of the microphysical world and of probability, he argued for realism and an objective understanding of probability. Later, he was to develop his own "Propensity" interpretation of the probability calculus.

On the mind-body problem, leading neurophysiologists such as Sir John C. Eccles found that Popper's idea of World 1, World 2, and World 3 provides a better framework for their research than any materialistic or reductionist philosophies. Indeed, Popper and Eccles once collaborated on and eventually produced, inter alia, the monumental book The Self and Its Brain (1977). No other philosopher had been able to cooperate so closely with leading scientists.

In the non-scientific disciplines, such as economics and the theory of art, Popper was also a constant inspiration to many leading scholars. In 1985, a group of economists convened in Amsterdam to discuss the Popperian legacy in economics. And as regards the theory of art, many of the books by the art historian Sir Ernst Gombrich, such as The Story of Art (1950) and Art and Illusion (1960), were written with an acknowledged intellectual debt to Popper. Here, the Popperian ideas of tradition and of the logic of the situation helped Gombrich to explain artistic development in a much better way than those romantic theories which consider works of art to be mere expression of the artists' subjective emotional states. More to the point, Popper's ideas help in the formulation of a more objective theory of artistic development. According to this theory, works of art are solutions to current demands in the context of previous artistic heritage of techniques and conceptions. Such solutions are, at the same time, underpinned by the framework of our perceptual mechanism and other psychological constitutions.

Popper was also a professed indeterminist. But he fully realised that indeterminism is not enough. Although philosophers had long been dissatisfied with Aristotle's classification of material, formal, final, and efficient causes, there was a tacit assumption by default that the only type of cause which one can respectably and scientifically talk about is what Popper called "cast iron control"--the necessary and sufficient antecedent conditions which determine an outcome down to the smallest detail. Unlike the usual indeterminist who pleads the case for chance or for free will, Popper worked on alternative types of causal mechanisms. This idea was first propounded under the name "plastic control" in a pamphlet entitled Of Clouds and Clocks, later reprinted in his Objective Knowledge (1972). Although work in this direction was far from complete before his death, one of the present authors has ascertained from Popper that he fully regarded "plastic control" as a causal mechanism and that it is irreducible to other types of causality.

The above are only a small sample of problems which Popper had tackled during his long, illustrious intellectual career, but even so, not another thinker in the 20th Century--not even Russell and Wittgenstein--could outmatch him in terms of the diversity of the topics, and also in terms of the stimulation which he had given to such a large number of academics from different fields. In this regard, to call him "the greatest philosopher this century" is not an overstatement at all. Indeed, The Sunday Telegraph (18th September 1994) used exactly this epithet as part of the heading of his obituary.

Naturally, one is curious to know what motivated Popper in his unquenchable thirst for knowledge--knowledge ranging from philosophy, cosmology, physics, politics, mathematical logic, the probability calculus, music, biology, psychology, economics, history, to the theory of speech and language. To this question, one might venture an answer: an insatiable intellectual curiosity with an unerring sense of where genuine problems lie in academic pursuit, and an unswerving belief in the progress of human knowledge. As the title of his autobiography suggests, it was an "Unended Quest" throughout his long life. Here, the present authors are able to give a testimony: We were most privileged to be received by him on four occasions, twice in July 1990, and twice in July 1992 (see my essays "Evolutionary Epistemology and Sir Karl Popper's Latest Intellectual Interest: A First-Hand Report" and "At 90, and Still Dynamic: Revisiting Sir Karl Popper and Attending His Birthday Party"), and vividly remember one of his remarks in the first of our four meetings. He first told us that his previous five strokes had weakened his memory and that he expected his life to end soon. But then he added that he nevertheless wished to remain active in his intellectual pursuit up to the very end. On hearing his remarks, we were moved beyond words. In contrast to such intellectual diligence, many younger philosophers, university professors and lecturers included, cannot honestly count as their academic forte a keen eye for genuine problems. Nor are they inclined to make relentless efforts to follow up on these problems, even in face of the vested interest of academic boundaries. Similarly, most people at his age who are stricken with illnesses are already tired of life. But not so with Sir Karl, who at our meeting still exuberantly talked about quantum physics and the origin of life. Although we had earlier heard about his energetic intellectual discussions with his visitors, we did not expect our exchange with him to be such an intense one.

As noted earlier, the Popperian tradition has all along been a major part of the intellectual foundation of our Institute. For instance, one of our Academic Technology Programmes in 1988 was devoted to the study of his Objective Knowledge. Then, in 1990, there was a 15-lecture course on the philosophy of quantum physics, which was based on his Statistical Interpretation of quantum mechanics and his Propensity Interpretation of probability. Furthermore, the first two of our IES Book Series were, respectively, the Chinese translation of his World of Propensities, and a festschrift (see my essay "IES Visitors Presented Festschrift to Sir Karl Popper") prepared on the occasion of his 90th birthday in 1992. There are two major lessons which our fellow members have learned from Sir Karl: first, to be always critical of our ideas and those of our colleagues; and second, to be always curious in a wide variety of subjects. This is why IES, while considering economics to be its chief interest of study, nonetheless regards him, and not any economist, as our intellectual beacon. Also this is why we have organised so many talks, seminars, and lecture courses on subjects unrelated to economics. In the days that follow, he will still be The Thinker to whom IES finds the closest scholastic attachment.