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Critical Rationalism (3)
Updated: 27 December 1999
We have seen that the practice of confirmation can give us no confidence in our generalisations. Yet generalising and abstracting from specific instances in the real world is the most powerful feature of human thought. It enables us to predict things in the future, respond to situations we have never encountered before in a rational way, and reason productively about the connections between and the causes of things. Scientific laws and theories are often regarded as the most reliable kind of knowledge we have.
What's wrong here? Do we always have to believe that our knowledge is uncertain and dependent on the pure chance that we have hit on the right generalisation? Some philosophers may argue from this that all knowledge is totally uncertain, that there is no knowable physical reality, that all knowledge is relative to the culture of the person concerned, and so on.
But Popper argued that, although absolute certainty about things in the world is impossible, there is such a thing as objective knowledge about the world, and that with the right method we can always approach closer to it.
Turning confirmation on its head: falsification
Popper pointed out that, although you can't confirm a generalisation, you can falsify it. In the simplest cases, all you need to do is find a counter-example to the generalisation, for example, a swan that is not white.
This suggests an (in principle) straightforward method of testing theories. Instead of looking for confirmation of a theory, which carries no guarantee of the truth of the theory, and may waste a lifetime, it is much better to look for counter-examples to the theory. This may mean that the theory is quickly disproved and abandoned, but so much the better, because a bad theory is a waste of time and a hindrance to the advance of knowledge.
If we have a theory, it should predict new observations. We test those predictions against all the new evidence we can find, in an attempt, not to prove it, but to disprove it. If, despite all our efforts, the theory still survives and explains the new evidence successfully, we can at least be sure that the theory is better than all the others yet advanced.
This attitude encourages radical thinking. Instead of hanging on to dead ideas, we should try out new ones all the time, but subject them to the severest of criticisms. Hence the name, "critical rationalism", We should be daring in our hypotheses, but once we have created them, we should be rigorous in testing them against observation and experiment, and willing to ditch them when they fail the tests.
Of course, trying to disprove your own ideas runs counter to what many people would regard as "common sense", but so also do many of the discoveries of science. Reasoning involves questioning the lazy assumptions of "common sense".
Two misunderstandings about Popper
To try to clear up one common misunderstanding: Popper did not suggest that unfalsifiable statements are necessarily "meaningless": this is an idea of the logical positivists that does not apply in critical rationalism. There are many areas of human thought in which meaningful things can be said but for which the falsification criterion may not be appropriate. These include ethics, aesthetics and religious thought, for example, except where they claim to make objective statements about the external world.
Another confusion is with the linguistic philosophers, who insisted that the important thing is to define the words that you use. On the contrary, critical rationalism insists that the important thing is to tackle profound problems, not to fuss over word meanings. The idea is to express problems in such a way that you can devise appropriate solutions for them, and test the solutions against new evidence.
How can critical rationalism be used?
Many scientists now use Popper's philosophy as a guide. The cycle of hypothesis and criticism fits in well with the long-established practice of peer review of all research before it is published in scientific journals. This practice ensured that a critical process was applied to scientific results and theories long before Popper described what was happening.
Of course, no critical process can guarantee absolutely against fraud and error; the activity of science is a human activity, and no human activity can ever be perfect. CR tells us that we have to live with this, but that we can at least do the best possible in the circumstances.
Popper did not stop at science, though. He applied the ideas of CR in other fields of thought, in particular the philosophy of politics and society. Popper's life included the periods of the major totalitarian philosophies of the 20th century, Nazism, Soviet communism and Maoist communism. Much of Popper's thought was concerned with the nature of authoritarian systems, and how they obstructed rather than enabled the pursuit of human ideals.
He promoted two main ideas here. One was the idea that progress (however you conceive it) must require the freedom to subject all ideas to rigorous criticism, because otherwise false ones may flourish. This requires an open society where debate and criticism are freely allowed.
The second idea is that there is no inevitable "march of progress". Both Nazism and communism promoted some kind of ideal future that each was inevitably bringing about in its own way: this notion is called historicism. In fact, human activity brings about both intended and unintended consequences, and the unintended consequences are by their nature unpredictable. We need the open society, so that all political and social activities can be openly monitored and freely criticised and corrective action taken in the political sphere.
Popper covered these ideas in his books The Open Society and Its Enemies (two volumes) and The Poverty of Historicism. In particular, he is known for his critique of Marxism, the driving force behind early communism, and one of the major influences in 20th century thought.