Karl Popper: philosopher of critical realism.

Sir Karl R. Popper, who died in September 1994 at the age of 92, will be remembered as one of the most influential philosophers of the twentieth century. Although German was his native language, he was accomplished in his use of English to explicate humanistic values. Many regard him as the century's most prominent philosopher; others point to his most famous work, The Open Society and Its Enemies, an unsurpassed defense of human liberty and dignity.

Referring to himself as an agnostic and an advocate of critical realism, Popper gained an early reputation as the chief exponent of the principle of falsification rather than verification. In the early 1930s, he set forth powerful criticisms of logical positivism's attempt to label as meaningless all talk of ethics and metaphysics. But for almost two decades, Popper's criticisms went either ignored or misinterpreted by all except a few careful readers. By contrast, in the past four decades, an increasing appreciation of his critique has helped us to better understand the phenomenal growth of scientific theory and the close relationship between science and the humanities.

Myth and Metaphysics. In his books Objective Knowledge and Conjectures and Refutations, Popper demonstrates brilliantly the roles of myth and metaphysics in the scientific enterprise. Myths represent our human need to expand the horizon of explanation and to find our place in the vast scheme of things. Emphasizing the importance of boldness of imagination in fulfilling this need, Popper suggests that Democritus' early theory of atoms began as a myth born of a daring imagination.

Myths sometimes graduate to the status of metaphysics when subjected to sustained and rigorous criticism. Metaphysics is the work we do when we carry out comparative analysis of our cosmological myths and theories. It is our drive to eliminate inconsistencies, to broaden the scope of our explanations, and to provide depth of detail. If there are priests of myth who insist on perpetuating the myths without correction or revision, there are others among us who both subject the myths to criticism and offer rival theoretical explanations. Of late, the term metaphysics has been adopted and used to propagate the uncritical and highly anthropomorphic notions of pop culture. This is not the tradition of rigorous metaphysics of which Popper speaks.

Far from being meaningless, critical metaphysics and cosmology provide the cognitive background for the growth of scientific theory. Logical positivists failed to see that, without metaphysics to work upon and to refine, science would stagnate. In some ways, science is the metaphysics that succeeded in spawning bold theories which are not only well articulated and critically debated but also observably testable--and by testable, Popper means falsifiable.

Falsification. Perhaps the major contribution made to science by Popper emerges from his argument that the job of scientific experiment is to seek evidence not to support a proposed theory but, rather, to refute it. He contends that science becomes mere ritual, making only meager progress, when it settles for testing to verify a favored hypothesis. The real task of experimental testing is that of trying to find the hypothesis' weaknesses and flaws. One way to put a theory or hypothesis to the test is to draw from it predictions about observable events in time and space. A theory becomes scientific when it is specific enough to be falsifiable and when it covers specified events observable in time and space. It ceases to be scientific when it hides behind vagueness or risks no bold and daring predictions going beyond the general consensus.

According to Popper, the whole point of seeking to shoot down our scientific theories is not simply to increase our supply of skepticism. Rather, the goal is to generate better theories--ones which are both bold and able to stand up under rigorous criticism without resorting to verbal tricks and vagueness. Popper's humanism shines brightest when he urges us to seek out criticism of our theories. Intellectual courage and honesty in uncovering contradictions are thus essential to the search for both better explanations and better plans of action.

Skeptics and Believers. Those who call themselves skeptics sometimes quote W. C. Clifford: "It is wrong, always and for everyone, to believe anything upon insufficient evidence." Unfortunately, Clifford gives no rational hint as to how many pieces of evidence total up to being sufficient. Thinkers strongly influenced by Popper's (and David Hume's) arguments against induction will be skeptical of Clifford's claim. Instead of advocating that we pile up sufficient positive evidence to prove or verify a belief, Popper offers an entire new way to think about testing our beliefs and corroborating them. I confess that I find Popper's epistemology more convincing than either the verificationists and conventionalists, on the one hand, or the dogmatists, on the other hand.

Furthermore, Popper's epistemology makes no fetish of either skepticism or faith. I know of no one who practices either wholesale skepticism or wholesale faith. All believers in certain claims are skeptics about rival claims. And all skeptics regarding some claims are believers regarding other claims. All of us, however, have pockets in our lives in which we would be better off if we showed more faith or trust. At the same time, there are pockets in which we would be better off if we trusted less--or at least shifted our faith to something or somebody more trustworthy. Trust and faith, like skepticism, are essential ingredients to human living. Skepticism per se is neither the enemy nor ally of faith per se, for the simple reason that neither exists.

Errors and the Search for Better Explanations. If to err is human, then Popper's philosophy may be regarded as perhaps the most thoroughgoing attempt to humanize the learning process, for he regards all learning as trial and error. Our mistakes in solving problems need not be viewed as failures but as a means for spawning still better solutions. This is especially true both when we try to learn how our mistakes were made and when we free our imagination to try out new conjectures.

Imagination and Intuition. The beauty of Popper's evolutionary theory of knowledge lies in its insistence that imagination and speculation are essential ingredients of the thinking process. Intuitions become a part of every variety of genuine thinking, including science, because they are accepted as trials rather than dogmas.

Most of our scientific intuitions and conjectures have proved to be unsatisfactory. But Popper argues that some falsified theories have contributed more to the growth of science than have safe, shallow theories that no one has bothered to falsify. Science needs fruitful and falsifiable hypotheses that not only venture into new territory but seemingly go counter to common sense. "Let your hypotheses die for you," Popper proclaimed. His epistemology is truly liberating, saying in effect that we should not worry about our theories cracking or collapsing because there are always more where they came from.

Creationism and Evolution. Creationists who insist on classifying their views as "scientific creationism" may not know what they are getting into. Do they really want to assert that creationism is falsifiable? Do they want to try to expose its weaknesses and flaws? Do they seek to correct and revise the doctrine? As is well known, creationists take great delight in pointing out that the theory of evolution is, after all, a theory. But this should pose no problem. All scientific theories are theories. Do creationists want to say that creationism is a theory? Do they want to say that the notion of the Bible as inerrant revelation is a theory?

If Popper's analysis is correct, then both evolution and creationism are theories. The real question has to do with how well they are articulated, how well they serve to advance further research, and how well they survive rigorous criticism. The overwhelming majority of biologists and anthropologists have found creationism to be a poor rival to evolution in the attempt to expand our knowledge. Contrary to what some creationists claim, scientists tend to favor evolution as an explanatory theory not because of some presupposition that blinds them to the truth but, rather, because it is scientifically more fruitful than creationism and enjoys greater explanatory power.

Biases and Presuppositions. One of the significant advantages of Popper's philosophy is found in the way it handles biases and presuppositions. In effect, it says that we always start with biases. Furthermore, we can never free ourselves of biases for the simple reason that they are essential to thinking. It is good to have biases, for they provide us with the raw material to examine, criticize, and revise or replace with new and (we hope) better biases.

Some evangelical theologians make a great deal out of presuppositions. They charge that evolutionists presuppose from the start a naturalistic rather than theistic framework. This charge is not entirely accurate, for there are theistic evolutionists. But according to Popper's epistemology, since a presupposition is only a conjecture or conclusion used to help spawn other conjectures, there is no reason why presuppositions cannot be debated and criticized. They have no diplomatic immunity.

According to Popper, objectivity is, therefore, not a psychological state of mind purified of all biases and presuppositions (he never confuses an open mind with a blank mind) but, rather, a two-pronged openness: openness to severe criticism and openness to look into alternative or even rival theories.

Indoctrination. Popper's theory of learning not only allows for indoctrination but requires it. Many humanists have been perpetually ambivalent about whether or not to indoctrinate the young into humanistic views and values. Indeed, some humanists in the past seem to have believed that objectivity or openness of mind required weak indoctrination. From the perspective of Karl Popper, by contrast, indoctrination should be thorough, not in the sense of shutting off all criticisms but in the sense of being done competently and by someone who is informed and articulate.

Popper sees the importance and necessity of indoctrination. Without it, there could be no education or objective inquiry. Humanists need to understand more clearly that each generation needs to be indoctrinated in humanistic values if these values are to be improved and passed on from generation to generation.

Although indoctrination is an absolutely essential ingredient of education or objective inquiry, it is never a sufficient ingredient. Indoctrination moves toward education only as it is combined with openness to criticism and to rival indoctrinations, views, conjecture, theories, and doctrines. Such openness of inquiry gives humanists hope that their humanistic convictions, commitments, and beliefs will in the future be even more profoundly articulated and more effectively communicated.

The Human Community. I close with a quotation from the last paragraph of John Dewey's little book, A Common Faith. It gives voice to much of the thrust of Karl Popper's work and life:

We who now live are parts of a humanity that extends into the remote past, a humanity that interacts with nature. The things in civilization we prize most are not of ourselves. They exist by the grace of the doings and sufferings of the continuous human community in which we are a link. Ours is the responsibility of conserving, transmitting, and expanding the heritage of values we have received [so] that those who come after us may receive it more solid and secure, more widely accessible and more generously shared than we have received it.