The German word for “courage,” Mut , is verbal cousin to the English word “mood.” But unlike English, German can play variations on that root by attaching prefixes to specify the mood. For example, Anmut means “charm” and Hochmut “arrogance.” That esoteric factoid from the world of etymology came to mind while reading Wittgenstein’s Poker , for in effect the authors, both journalists for the BBC, have written a most charming book about a brief ten“minute contretemps (their only encounter) between two men, Ludwig Wittgenstein and Karl Popper, who will strike most readers as either admirably courageous or intolerably arrogant (or both).

Of their arrogance there can be no doubt. As the authors write, “Whatever the social and cultural differences between Wittgenstein and Popper, one similarity of character made it inevitable that [the audience at their debate] would see a raging confrontation: their sheer awfulness to others in discussion and debate.” Popper was especially unyielding in public argument. He would even occasionally demand that his graduate assistants ask prepared questions at his lectures, rather as if he were speaking at a plenary session of the Moscow Communist Party, and would then berate them in public if the wording of their questions strayed from their prepared text or, worse, so much as hinted at any inadequacy in his views. This obnoxious habit prompted one wag to claim that Popper’s most famous book, The Open Society and Its Enemies, should instead have borne the title The Open Society by One of Its Enemies . As for Wittgenstein, he left one woman in tears (his hostess at a weekend outing no less) when she exclaimed, “What a beautiful tree that is!” This quite ordinary bit of small talk prompted him to turn on her and harshly demand what she could possibly have meant by such a vapid remark.

But both men no doubt also displayed courage, and often. Wittgenstein fought for the Austro“Hungarian Empire in World War I and proved brave to the point of foolhardiness. So courageous was he in one battle that he would have won a medal for heroism except for the fact that Austria lost that particular battle, and the Hapsburgs, in their typically ham“fisted, Ruritanian way, only gave out medals when the army as a whole was victorious. And Popper never tempered his views in public lectures even when it would have done his career some good, so that after he fled Hitler’s post“ Anschluss Austria he had to wander about like the Flying Dutchman until finally settling in the London School of Economics well after the war.

Despite these similarities, what one most notices in this pleasantly written book is their differences, especially their different”indeed incompatible”conceptions of philosophy. For Popper, philosophy was supposed to solve real problems, both political and scientific, and for that reason it cannot be accidental that the former Conservative Prime Minister of Great Britain, Margaret Thatcher, and the former Social Democrat Chancellor of Germany, Helmut Schmidt, both called Popper their favorite philosopher. As for scientists, most of them manage to get along quite well, thank you, without the ministrations of philosophy, but those who take an avocational interest in its issues also have only the highest praise for Popper.

Wittgenstein, on the other hand, considered philosophy to be little more than a matter of solving “puzzles,” as he called them, generated solely by the tricks that grammar plays on logic. Any other approach was for him “bad philosophy.” As he once said, in his typically witty and aphoristic way, “Bad philosophers are like slum landlords. It’s my job to put them out of business.” Not surprisingly, Wittgenstein is one of the most popular philosophers among other philosophers, who rather seem to enjoy trying to put each other”especially members of rival schools”out of business. But his influence on practicing politicians or scientists, who presumably prefer working on crosswords when in the puzzle“solving mood, is next to nonexistent.

Although both grew up in a Jewish section of Vienna and both hovered around the outer penumbra of the so“called “Vienna Circle” (a group of local, mostly Austrian philo­ sophers who founded the school of Logical Positivism), Popper and Wittgenstein never actually met until a fateful debate before the Moral Sciences Club at Cambridge University on October 25, 1946. As it happened, the debate was precisely on the topic that most divided the two men: whether philosophy was meant to deal with Popperian problems or Wittgensteinian puzzles. But Popper had no sooner begun to speak than Wittgenstein grabbed a fireplace poker and began brandishing it about”according to some threateningly, according to others simply to gesticulate. Here accounts really begin to differ, for at this point Wittgenstein either did or did not storm out before Popper”when asked to name a moral rule”either did or did not get off the clever rejoinder, “Not to threaten visiting lecturers with pokers.”

Nobody present at the time, it seems, can give an agreed“upon account of that evening”any more than philosophy has ever resolved the issue of its true mission, which seems to be the point of the book. Take, for example, Popper’s famous “falsifiability principle,” his counterproposal to the “verification principle” of the logical positivists. According to the latter school, a theory counts as true if the accumulation of verifiable evidence tells in its favor. But of course, that begs the question not only of what counts as evidence but perhaps even more crucially of how long that evidence needs to continue to tell in favor of the theory. How much evidence must one require for a theory to be taken as true? If one takes the verification principle seriously, one must insist on an infinite range of evidence, covering all cases. As Bertrand Russell put it in an amusing example: “The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken.”

Thus for Popper (as for David Hume before him) a scientific theory could never be proved conclusively true; at best it could be held as provisionally true, pending further inquiry. If science really wants a more serviceable theory, then for Popper one must devise one that can be falsified, not verified, by evidence refuting, not supporting, it”just as the benevolence of the farmer toward the chicken was refuted on the day the chicken was served up in that evening’s soup.

But how might that apply to the differing versions of the debate on the evening of October 25, 1946? Wittgenstein’s Poker includes as an appendix a 1998 debate in the Letters column of the Times Literary Supplement , during which most of the surviving attendees of that now notorious ten“minute debate discussed the event. Not only are these accounts by and large contradictory to each other, there really is no way at this juncture, over a half century later, to falsify them, at least short of holding a mock trial in a moot courtroom, with all surviving witnesses subpoenaed under penalty of oath.

But surely this sort of dispute is a regular feature of all eyewitness accounts of long“past (and even recent) events and, a fortiori, of all history. Must history therefore be ruled “unscientific” in all its forms and genres because its statements are difficult, and at times even impossible, to refute? For example, one recent theory holds that the Roman Empire declined and fell not because of Christianity, as Edward Gibbon maintained (or at least implied), but because the Romans invented lead piping to bring water into cities from their fancy new aqueducts, which, in turn, produced lead poisoning and sterility. How would one ever begin to refute either view under Popperian rules of evidence, or even establish their incompatibility?

Consider also Popper’s current influence. As the authors rightly point out, “His name is fading, if not forgotten.” Partly, this represents merely the penalty of success: what needed saying in 1946 at the outset of the Cold War has now become the received wisdom since the collapse of the Soviet Union (although the authors mention that as late as the year 2000 a Chinese academic, Liu Jumning, was evicted from the Chinese Academy of Social Sciences after delivering a lecture on The Open Society ; and, Lord knows, the House of Islam could certainly use its own native“born Popper).

But Popper is not just the victim of his own success, but of Wittgenstein’s as well. By a great irony, universities swept away by postmodern trends have also largely forgotten the prescience of Popper’s ringing defense of the Open Society, so that (partly under the influence of Wittgenstein’s theory of language games and of his notion of meaning as determined by social usage, not “things in themselves”) such philosophers of science as Paul Feyerabend and Thomas Kuhn have argued that scientific theories are not as humble as Popper would lead us to believe. They are rather paradigmatic impositions by the hegemonic or pragmatic intellect. As Wittgenstein himself put it: “If I have exhausted the justification, I have reached bedrock and my spade is turned. Then I am inclined to say, ‘This is simply what I do.’” But when that point is reached”when, that is, action alone and not argument can justify itself”then mutually conflicting actions can obviously be tested only against the power behind each actor.

In this sense at least, Wittgenstein won the debate, for now everything looks like either pragmatic expediency (“this is simply what I do”) or hegemonic Will to Power. As to philosophy itself, it has very little of the public presence that Popper had given it. By and large, puzzles govern topics for debate, not problems, or at least not the problems that might merit the attention of, let alone have any influence on, practicing politicians or scientists.

Perhaps this is why the authors conclude their generally cheerful and bemused account of these two high“strung geniuses on a certain elegiac note: “Tolerance, relativism, the postmodern refusal to commit, the cultural triumph of uncertainty”all these rule out a repeat of the pyrotechnics of [that evening]. Perhaps, too, there is currently so much specialization, and so many movements and fissures within higher education, that the important questions have been lost.” In other words, it would seem that not only do Communist China and the House of Islam need another Popper. So, too, does the world of higher education in the West.

Edward T. Oakes, S.J., teaches in the Religious Studies Department at Regis University in Denver, Colorado.