No Pepper

I would like to add some points of correction and clarification. First, Karl Popper distinctly and unequivocally denied that verifiability is either how science works, or the way to true knowledge. His criticism of many of his contemporary epistemologists at the time who were fixated on science and its alleged use of a "method" which relied on the verifiability of all scientific claims, was an old one; Popper showed that verifiability was subject to the same problems that 18th century English philosopher David Hume showed as the logical problems of induction. Hume showed that making universal statements based on a finite number of observations was logically fallacious and unsound. Hume showed that the inductive process which many philosophers and natural philosophers (we'd call them scientists today) claimed as the basis of science at his time was therefore logically unsound. Popper showed in his work in the early to mid 20th century that verifiability was subject to the same logical problems as induction, and that scientists and philsophers who claimed science distinguished itself from other human endeavours by reliance solely on statements that were verifiable were therefore logically unsound too.

Popper chose to save science from itself and the verificationist philosophers that deified it by claiming that scientists might believe that they operated by verification, but in fact they did not. Popper argued that instead what scientists did was a similar but logically very differnt thing. Science, he said operated by a process he called "falsification" and scientific claims were all "falsifiable". That is, he recognized that universal law-like statements were made by scientists, and that in and of themselves these statements could therefore never be proven to be true based on non-universal, or a finite set of observations. However, Popper pointed out, such universal statements could be disproved by only one observation that contradicted them. This, therefore, was the way that science operated, Popper concluded (unfortunately Popper really didn't look any more closely at what scientists actually did than anyone before him, he only concluded that they must be rigorous falsificationsists if they were to be good logical scientists and concluded that this is what science "did" because this is what it "ought" to do to be the rigorous discipline that was unlike all other kinds of human endeavour).

To illustrate the difference between "verifiability" and "falsifiability", we can consider the following statement. "The Sun rises in the east in the morning and sets in the west in the evening." It is "verifiable" in the sense that an observer can check to see if this indeed is the case for many days and draw the conclusion that this is a univeral law from many verifying observations. Hume and Popper point out that one can never logically conclude that simply because an event is observed to repeat itself many times that it will always and forever do the same. This is the problem of induction; it is illogical and unsound to conclude from a limited number of observations that some statement is universally true.

However, if we consider the same statement again we can immediately see the power of falsificationist philosophy and why it was so influential among scientists and philosophers of science in the first 60 years of the 20th century (regardless of whether scientists actually did use a falsificationist approach!). If, instead of collecting numerous pieces of data that verified their theory (universal statement), what scientists allegedly really did was try and try again to look for the one observation that falsified their theory then they were on logically solid ground and genuinely adding to human knowlege. While no universal statements about the world can be known to be true, we can know, Popper said, know which universal statemtents are not true, or have been falsified. For all it takes is one instance where the sun did not behave as described and the theory would be falsified and a new theory would have to be invented to replace it, which would then be subjected to the same rigorous efforts to falsify it as the previous theory.

In any case, Popper, while having much in common with logical positivists and other philosophers of science in the early 20th century that were fixated on objective knowledge from observation, Sir Karl was very different in the role that observation played in science. Theories were not verified (for indeed they could not be as Hume had shown long before him), but they were falsified; well fomed theories were not verifiable, they were instead falsifiable.

A final point about Sir Karl Popper (yup ... a German knighted by the English in the mid-20th century ... not many of those!): if you are looking for the most generally influential philosopher of science of the 20th century one should probably pick not Karl Popper, but rather Thomas S. Kuhn (author of "The Structure of Scientific Revolutions", a book so outrageously influential in so many fields that many are unaware they are quoting him or using his ideas in so many fields so far flung from Philosophy of Science that it defies belief. "Gestalt" ... a word borrowed from somewhat obscure works on psychology, and forced into the mind of the 20th century by Kuhn. "Incommensurable" ... Kuhn. "Paradigm" ... almost always used today as Kuhn discussed it. "Paradigm Shift" ... Kuhn.

Anyway ... you can all now return to your regularly scheduled ball game.

J.A.I. (B.A., M.A. Candidate at University of Toronto's Institute for the History and Philosophy of Science and Technolgy).