Monday, November 08, 2004

POPPER AIN'T SO DAPPER!: MUSINGS ON KARL POPPER, VERIFICATION, FALSIFICATION, AND THE EXCLUDED MIDDLE.



For some time now, I have wanted to make an entry about the famous philosopher, Sir Karl Popper (1902-1994) and his ideas. Popper, who is most well known for his idea of ‘falsification’, has been on my mind for a long time now. I languished for all that time, trying to get my thoughts into order. Since philosophy itself is a slippery discipline, it is always hard to get your thoughts about it into perfect order, let alone express them succinctly. So what I am going to say will most probably be a bit garbled and confusing, and certainly not complete. But instead of waiting for an infinite time before achieving perfection, which will never come, I thought I would go ahead anyway, and follow up on this post whenever I get fresh inspiration.

I probably wouldn't have written about Popper at this time, had it not been for my perusal of a marvelous article titled 'A skeptical look at Popper' by the eminent philosopher and expositor of Mathematics, Martin Gardner (Gardner, 'Skeptical Inquirer’, July/August, 2001, pg. 13). It was a revelation, not only for the typically enlightening style in which Gardner has written it, but also because it surprisingly mirrored some thoughts about Popper's ideas that I had quite independently. Ironically, these thoughts of mine had originated as a result of puzzlement, rather than as a product of detailed analysis.

Although I can never claim to be close even to being an amateur philosopher, what surprised me was how naiveté such as mine can actually lead to valid questioning. This instance may provide an explanation of why children's ideas are sometimes much more insightful and probing than those of even established professionals in the field. They are not clouded by bias and the hubris of higher education and achievement. The lesson I learnt from this experience, quite curiously, is that sometimes it's better to actually not read too much about something, instead giving yourself a chance to think independently about it for a while, before you make a foray into wider and greener pastures.

Sir Karl Popper was one of the most distinguished philosophers of the century. Many people have no problem placing him on the same pedestal as Bertrand Russell and Ludwig Wittgenstein. That he was brilliant is undisputed. Popper was born in Vienna, the son of a wealthy lawyer. He was trained in Philosophy and Mathematics, although he never would have a formal degree in science (This also marks him with the unique distinction of being the only 'non scientist' as such to be elected to the Royal Society of London). Early in his life, he was exposed to the famous 'Vienna Circle' of Philosophers, whose philosophy of 'logical positivism' aimed to establish Philosophy on the same secure basis as science. The members of this circle, people like Kurt Gödel, Rudolf Carnap, Moritz Schlick and others, would go on to make fundamental contributions to logic, mathematics and philosophy. Right from the beginning, Popper could never reconcile himself with logical positivism and hence always remained an underdog outside this elite circle of intellectuals. I will describe their ideas and Popper's opposition to them shortly, but first let me finish up the shortened story of Popper's life. When Hitler came to power, Popper, like many others, sought to escape Germany's vehement policies and anti-Semitism. Because he was not deeply affiliated with the Vienna Circle, he could not rely on the prestige of its members to land himself a decent job in another country. Persistent efforts finally got him a lectureship in Christchurch, New Zealand, where he essentially lived out the war. While in New Zealand, he wrote what many consider to be his most important work, 'The Open Society and its Enemies', which was essentially an attack on totalitarian regimes. Another reason why the book received a wide audience was its severe critique of Plato's ideas, especially as enumerated in his famous 'The Republic'. According to Popper, Plato's ideas were among the first ones to support totalitarianism. The book turned out to be Popper's claim to fame (he called it his 'contribution to the war effort'), and after the war, he was offered a Professorship at the prestigious London School of Economics, where he stayed until his death at the ripe old age of 92.

Popper grew up in a period, which was witnessing great scientific, philosophical, and political upheavals. Albert Einstein had proposed his brilliant General Theory of Relativity in 1917. The Quantum Theory had begun to take root with Niels Bohr’s model of the atom in 1913. In parallel, Europe had gone to the most destructive war it had ever seen. Political ideologies were rampant, especially in Russia and Germany, ideologies which would have devastating and permanent effects on the future of society.
At the same time, philosophy was witnessing another revolution. Popper was fortunate to have lived during those times in Vienna, a place that was really the center of culture, music, art, science and philosophy. Austrian philosophy in fact dominated world philosophy at the time, through a remarkable group of men, whose inspirations were Einstein, Bertrand Russell and Ludwig Wittgenstein.

This group was called the ‘Vienna Circle’. Their goal: to make philosophy more or less an exact science. In philosophy, as in other non-natural sciences, the big question is that of truth and falsity. How can we decide if something, anything, including a statement, is ‘true’ or ‘false’? The Vienna Circle apparently saw a way out of this profound conundrum. The fundamental tenet on which they based their musings was Francis Bacon's 16th century idea of ‘induction’, a process which had it’s origins in Aristotle’s philosophy, and which had been the basis of scientific and rational thought for centuries. Today, it is better known as ‘empiricism. In the 18th century, David Hume had pointed out the problems with induction. For example, consider the statement, ‘The sun rises in the East’. Is there any way to actually ‘prove’ this? The only reason we say that it is true, is because the sun has continued to rise in the East as far as man can remember. Implicit in this reasoning is a method for verifying this fact, by making observations. This was the method which the Vienna Circle banked upon. To reinforce this point, they reduced all ‘true’ statements to mean statements which are verifiable: they called this dogma the ‘Verification Principle’. Simply put, the truth-value of a statement rests on its verifiability. So if I say that some object is ‘red’, that means that I should be able to provide a method of ‘measuring’ the quality called ‘red’. The exact method may be disputed, but for the Vienna Circle, the fact that a well-defined method for verification of a conjecture exists at all is the only proof of the truth of that conjecture. To put it another way, philosophy is reduced to the scientific method of verification and induction.

Unfortunately, there are problems with the Verification Principle that immediately come to mind. For example, if someone says that she has a headache, then is this statement true only if it is ‘verified’, that is, only if say, she takes a headache pill!? This particular way of doing things seems odd, to say the least. But there is another fundamental problem with verification, one that is inherent in its nature and also in that of induction. The most famous example consists of the statement ‘All crows are black’. What is the proof of this statement? According to the Vienna Circle, the moment we make an observation and see a black crow, the statement is verified. Or is it? The problem hinges with the word ‘all’. This word guarantees that no matter how many black crows we see, there may just be a white one around the corner to refute the statement! So no matter how many observations we make, we are still stuck. Another profound problem has to do with the method of induction which we are using. What justifies it? As Hume pointed out, there is no way we can deduce the principle itself from first principles. So the only way that it can be justified is by noting that it has always worked, and so it should work in every future case too. In a nutshell, we are using induction to justify the use of induction! Such kind of self-referential methods are the bane of logic and philosophy, as Kurt Gödel, one of the members of the Vienna Circle, himself later proved. As long as we cannot justify induction, and as long as we cannot verify a statement exhaustively, the method of verification is left to cool its heels while the fate of every statement such as ‘All crows are black’ hangs in balance. How do we get around this problem? Enter Karl Popper.

Popper’s contribution to modern science and philosophy rests on his crucial observation that no number of observations is enough to justify the validity of a statement, as we saw above: however, a single negative observation is enough to invalidate the theory. In the case of our crows example, a single observation of a white crow instantly renders the statement ‘All crows are black’ as false. So to say, the real value and decisiveness of a scientific theory lies not in its verification, but in fact in its falsification. This ‘Falsification Principle’ of Popper’s has been long exalted as a fundamental standard to which scientists must subject their theories. Thus, according to Popper, once someone comes up with a scientific theory, all his peers have to do is to concoct experiments which will refute his theory. If the theory passes these norms of falsification, it proves itself as a golden model of science. The appeal of Popper’s theory lies in its ability to decide, once and for all and abruptly, whether a theory is scientific or not. Therefore, Popper gave the world a powerful tool for doing something which is profoundly important, separating science from non-science.

I first read about Popper and falsification in John Casti’s fantastic appraisal of modern science and society, ‘Paradigms Lost’. I was struck by the decisive power of the idea, but something was missing, something about it was not-so-decisive, something which gnawed at my mind but which I could not put my finger on. Some of the problems with Popper’s concept of falsification have been articulated by philosophers themselves. The most important among these is called the ‘Law of Auxiliary Hypothesis’. Coming back again to our enduring problem of black crows, Popper says that a single observation of a white crow is enough to repudiate the hypothesis. But suppose the crow is originally a black one purposefully painted white to deceive us. Or suppose there’s a mutation which has caused it to become white. In such cases, there is no problem with our original hypothesis, but there is a problem with some secondary or auxiliary principles which we have tacitly assumed, in this case the facts that there can be no mutations and that nobody is going to artificially color crows to try to fool us. But it’s clear in such cases that falsification certainly does not invalidate our hypothesis immediately, but calls for further investigation. This raises other questions. How many such auxiliary hypotheses must we investigate? This genuinely is a problem with Popper’s theory. But in my case, the simple fact that naively jumped at me was this: whenever we falsify a theory, we are validating some other theory, in most cases its opposite. In fact, we may be validating not only another one but many other ones (since most things in life cannot be simply explained only by one theory or another, but demand scrutiny from many quarters). In that case, we would have to apply the same falsification to all the other theories, until we automatically validated the last surviving one. So to me, falsification really seemed a great process of elimination, but also one through which we were in the end validating something or the other. That’s why, to me, falsification looked complementary to verification, not something that would usurp it. More importantly, I turned over the statement about the great value of falsification over and over again in my mind: as a superb tool for distinguishing science from non-science. And that’s when I thought about Cosmology. In Cosmology, we have many completely theoretical models, for example those of black holes advocated by stalwarts such as Stephen Hawking. Most of these theories stake their claim to valid science because they are supported on sound mathematical models. Experimental evidence for many of them, if any, is either fuzzy or simply impossible to gather in the present scientific setup. In fact, many of them may never be either validated or falsified. Would Popper characterize these as ‘non-science’ then? Or consider evolution, the great debate. The single most important fight scientists are waging right now is against the ‘creationists’ who claim that all of Evolution is hogwash, and that the earth was actually created a few thousand years ago, if not yesterday. In case of evolution as well as creationism, we are talking about extremely complex events that took place over an incredibly large period of time extending over millions of years. Most of the evidence that we have for evolution is indirect, and no matter how convincing it may seem, we definitely cannot directly validate it. Nor can we falsify it. So the bottom line is that we can never think of direct laboratory experiments, which can be done within human capacity, that can demonstrate any of the tenets of evolution. Ergo, according to Popper’s model, evolution is not a scientific theory, or at least not as scientific as, say Newton’s Laws of Motion. First of all, this notion raises the question of the ‘degree of scientificness’ of a theory. Secondly, I think that the fundamental problem with both verification and falsification is that they assume that scientific theories are of ‘either-or’ kind. Unfortunately, as we have seen, even in some of the best scientific theories of today, decidability is not absolute. Verification or otherwise is not decided by them being ‘true’ or ‘false’. There are shades of gray in them. Here, as in other aspects, science really models real life. It is not absolute but probabilistic. Can Popper’s theory handle probability? More importantly, what does Popper have to say about theories which are simply not falsifiable? And in fact, this raises a fundamental recurring theme in Philosophy, be it that of science or morality: are the theories of philosophy supposed to model the real world in the first place? Or are they simply artifacts of contemplation, occupying a world which is bereft of any connection to reality, designed for the entertainment of intellectuals in Viennese cafes? I am not demanding that philosophy should actually enable us to build a better mousetrap. But if anything, it should at least set standards and theoretical paradigms and constructs, which will aid our understanding of the world or of human nature and thought. What constructs does Popper provide us for the development of our discipline?

I pondered about these questions for a long time without finding definite answers, and still do. But the article by Gardner was a kind of redemption to me and gave me some relief. He raises many points which I thought of, in a much more organized and marvelously revealing way. Most importantly, he tackles the last question which we mentioned, and reaches a definite conclusion: as far as the real work of real scientists, be it social or natural, is concerned, Popper’s ideas do not provide much buttress. Ironically, the ghosts of verification in fact aid the work of scientific thinkers. Simply put, and quite obviously if we think about it, all modern scientists are engaged in verifying their theories, or those of others.
For example, astronomers look for water on Mars. They are not trying to falsify the fact that Mars never had any water. In another example, astronomers are now finding compelling evidence that smaller and smaller planets orbit distant suns. Surely, this is inductive evidence that there may be Earth sized planets out there. Why bother to say, as each new planet is discovered, that it tends to falsify the conjecture that there are no planets outside the solar system? Why, as Gardner wittily says, should we scratch our left ear with our right hand? The fact remains that in the real world, real science operates mostly by verification, and much less by falsification. In the ideological and infinite playing field of philosophy, verification may be seen as an incomplete unsolved puzzle, but in the real world, it is always a virtue. Gardner also mentions the exact thought that I had, that falsification of one conjecture is confirmation of the opposite one. But he says, somehow Popper dismissed this fact as unimportant. My take on it is that perhaps he dismissed it because of tacit assumption of the opposite: that confirmation of a theory is falsification of another one! The fact is, and this in my opinion is the bottom line: falsification is no more important than verification, and in practical life, probably less so.

So why the big fuss about it over more than half a century? As Gardner notes, this was largely due to Popper’s prestige. Karl Popper was a forceful man, one who would press his claim to priority as vehemently as he could, one who would make his opponents shiver in debate, one who would even lionize his own achievements, relegating others’ to unimportance. While he lived, he was probably the most prestigious philosopher of his time. In his iron rule of the philosophical arena, he cleverly managed to subjugate the value of verification. Part of the fault is not his. Falsification is important, undeniably so. But, as I doubted from the beginning, it is no more necessarily important than confirmation. Popper made verification look like its poor cousin, when in reality, I think that falsification is more aptly described as verification's half-brother, coming to our aid sometimes when other methods fail, but mostly being of marginal practical importance at most. I felt a satisfying feeling on reading Gardner’s article. I felt that some of my own feelings had been verified, and I must confess that this pleased me much more than if they had been falsified!

That Sir Karl Popper was one of the most brilliant intellectuals of the twentieth century is undoubted. His provocative contributions to knowledge have made us question our beliefs in understanding why and how. However, neither Popper nor anyone else can make the final claim on our understanding, questioning and reasoning. And it’s better that way. Because in the uncertain shades of these human attributes lies the wonder of the human spirit. And the wonder would endure only if these attributes are neither verified nor falsified.

2 Comments:

Blogger Sumedha said...

It seems that verification vs falsification can be likened to optimism vs pessimism :-)
A positive approach always wins in the end. Great post.

8:44 AM  
Blogger Ashutosh said...

That's a nice way of looking at it! The fact that we can only falsify something, but can never verify it, casts a gloomy shadow on our reasoning and existence!

10:43 AM  

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