Karl Popper

Sir Karl Popper (1902-1994) was an Austrian-born philosopher of science widely regarded as one of the greatest philosophers of science of the 20th century, who influenced the philosophy of science and politics.

Philosophy of Science

Falsifiability

In his seminal work, The Logic of Scientific Discovery, Karl Popper repudiated induction, and proposed the bright line of falsifiability as a demarcation between science and non-science. In order to be scientific, a theory must be testable, and the results of the testing must either corroborate the theory, or falsify it. A proposed theory is falsifiable, if it is conceivable to conduct an experiment that would disprove the theory. For example, Newton's law of gravity is a valid scientific theory because it is falsifiable; that is, the Law of Gravity is experimentally testable, and a measurement taken that violates Newton's law would falsify it, while a measurement that substantiates the theory would corroborate it.

While chemistry, Newtonian physics, and many other fields belong to science, metaphysics and pseudoscience are not scientific. Whilst it is commonly stated that Popper believed Evolutionary Theory to be unscientific, since he argued that it was tautological in 'Unended Quest' (1976), he in fact withdrew his criticism in 'Dialectica' (32:344-346), stating;

"I have changed my mind about the testability and logical status of the theory of natural selection; and I am glad to have an opportunity to make a recantation"

Universal Laws

The falsifiability criterion arose as a result of Popper's analysis of the logic of universal laws. Universal laws have a logical structure which precludes certain existential statements : universal laws are a negation of an existential proposition. Popper's example was that of the color of swans. The universal statement "all swans are white" implies the negative existential statement "no swans of a color other than white exist". To verify the negative existential we would need to trawl through the universe to ensure that no non-white swan existed anywhere in time or space. Conversely, if we saw just one black swan we could confirm the existential statement "black swans exist" and refute the universal "all swans are white".

Popper was uncompromising in his rejection of any attempt to take confirming instances as increasing the legitimacy, likelihood, reasonableness or probability of the universal statement. No matter how many white swans you see you are no more able to assume that all swans are white than if you had seen just the one white swan. The ease with which “verifying” instances can be found lead Popper to the conclusion that an attempted verification of a universal law is worse than useless: to be science universal laws must be capable of being put to the test, to be falsifiable.

Politics

A refugee from Austria after the rise of Nazism, Popper dedicated the war years to the study of the roots of totalitarian thought. The “Open Society and its Enemies” analysed the contribution, as he saw it, of Plato, Hegel and Marx to an anti-rational tribalistic “closed society”. The close society was, for Popper, marked by a lack of criticism of established ideas (established societal norms being treated not as societal norms but as “taboo” or “the natural order”) together with a collectivism that subjected the individual to the group goal. Popper also saw “historicist” views and underpinning much of the thought behind the “closed” society. “Historicism”, dealt with in “The Poverty of Historicism” and criticised throughout the “Open Society”, both sees historical laws of development and bases much of its morality on these supposed laws.

In contrast the concept of the "Open Society" reflects Popper's concept of science. Just as there is no method for generating a true description of a Universal Law there is no method for generating perfect (Utopian) social laws, norms or governmental actions. Society will always be in a state of less than perfection and may only improve by changing what was previously thought to be the best course of action. As society can only improve by self-criticism it follows that criticism must not be restricted.

The view is criticised by those who see positive value in tradition, ritual and shared belief per se. (A small scale example is the family Christmas tradition that most families have. They are usually dogmatically held and are of value precisely because they are dogmatically held: the shared dogma helps bind the family together). The view is also criticised by those who suspect our ability to decide on the full facts when looking at a social institution. All actions have unintended, unknown, consequences. We may simply not be aware of some functions of the particular institution, tradition or social norm being criticised. Avoiding rejection of institutions with good, but unknown, consequences necessitates some level of dogma to protect them.

Popper's views on politics cannot be placed along the traditional left/right axis. Bryan Magee, a liberal politician (MP for the British Labour Party and the British Social Democratic Party) who knew Popper personally, reflected that Popper began adult life an "emotionally committed social democrat" and moved, with middle age, progressively to the right. Magee reflected that the key insights given by Popper, the method of robustly critising our own views, "can be adopted by anyone committed to democratic politics, from the extreme democratic left to the extreme democratic right"

Critical Rationalism

In "The Open Society and its Enemies" Popper put forward the concept of Critical Rationalism in opposition to the Authoritarian rationalism of previous philosophers. Previous philosphers had assumed a central role of justification in knowledge, whilst Popper denied the very possibility of justification arguing that any attempt to establish a foundation for knowledge led to a regress ending in "faith" (in the sense of a belief held without conclusive reasons that is held to be uncriticisable). Popper characterised rationality not as a methodology of formulating and verifying proposition but as a constant criticism of existing beliefs.

In "The Open Society and its Enemies" Popper declared his "faith" in reason (as characterised by criticism). A faith that led him to reject any other epistemological authority. His student, W. W. Bartley III went further ("The Retreat to Comittment") and rejected the need to have faith in reason. For Bartley all propositions where criticisable, even the propositions of basic logic themselves, a position he termed "Comprehensively Critical Rationalism".

Another pupil of Popper's, David W. Miller rejects not only dogma, which can be characterised as support for propositions that should not be questioned but the very concept of "support".

"there exist no grounds whatever, conclusive or inconclusive, for anything that we know"[1]

The view is criticised by those who hold that knowledge must have foundations, basic beliefs that are both true and justified, from which other propositions are derived.

Sources

• Stanford, Encyclopedia of Philosophy (2006-10-09), Karl Popper, Stanford Encyclopedia of Philosophy Retrived on 2007-05-14