Sunday, February 18, 2007

Karl Popper - The Logic of Scientific Discovery (1934)

Karl Popper's 1934 Bombshell

In 1934 Popper published what many regard as his Magnum Opus The Logic of Scientific Discovery. In one majestic and systematic attack, psychologism, naturalism, inductionism, and logical positivism are swept away and replaced by a set of methodological rules called Falsificationism.

Falsificationism is the idea that science advances by unjustified, exaggerated guesses followed by unstinting criticism. Only hypotheses capable of clashing with observation reports are allowed to count as scientific. "Gold is soluble in hydrochloric acid" is scientific (though false); "Some homeopathic medicine does work" is, taken on its own, unscientific (though possibly true). The first is scientific because we can eliminate it if it is false; the second is unscientific because even if it were false we could not get rid of it by confronting it with an observation report that contradicted it. Unfalsifiable theories are like the computer programs with no uninstall option that just clog up the computer's precious storage space. Falsifiable theories, on the other hand, enhance our control over error while expanding the richness of what we can say about the world.

Any "positive support" for theories is both unobtainable and superfluous; all we can and need do is create theories and eliminate error - and even this is hypothetical, though often successful. Many superficial commentaries are keen to point out that other people stressed the importance of seeking refutations before Popper. They overlook the fact that Popper was the first to argue that this is sufficient.

This idea of conjecture and refutation is elaborated with an orchestration suggestive of someone who loves great music. (Popper loved Mozart and Bach, and took great pleasure in composing his own music.) The common idea that Popper neglected to consider whether Falsificationism itself is falsifiable is already scotched here. You can falsify a description, but not a rule of method as such (though obviously a rule can be criticized in other ways). The notion that science offers proof is now only advanced by popular treatments of science on TV and in (many) newspapers - most journalists (with a few important exceptions) are sadly completely devoid of theoretical knowledge: a side-effect of overspecializing on the immediate moment. But then, anyone can improve!

Most people who think they have a ready rebuff to Popper's position have never read his work. If they only read the original works, in most cases they would see that their supposed "Point that Popper neglected" had already been considered and exploded. A good example of this is Lewis Wolpert's remarks on Popper's works in his otherwise excellent book The Unnatural Nature of Science. He seems to think that Popper's falsifiability criterion ignores hypotheses about probabilities - overlooking the blatant fact that The Logic of Scientific Discovery devotes more than a third of its pages to the two fundamental problems of probability in an effort to find a solution that will also allow hypotheses about the probability of events to be capable of clashing with the evidence! Popper was in fact fascinated by probability and even produced his own axiomatisation of the probability calculus.



For the best current re-statement, defence and - more importantly - application of Falsificationism see David Miller's Critical Rationalism: A Re-Statement and Defence (click here for Amazon.co.uk). Miller was a very close friend and colleague of Popper's. He pulls no punches and is (despite his modesty) Popper's best knight. If you want razor-sharp logical accuracy, a full arsenal of arguments, and comprehensive demolition (with unrestrained collateral damage) of the opposition, Miller's book is the answer.

2 comments:

Anonymous said...

Where is the reference to the source of your post?

crabsallover said...

reference for post:
http://www.eeng.dcu.ie/~tkpw/