Finally: The Best Argument for Realism
A13 The failure of scientific theories may be explained by realism
The realist says: Theories fail because they are wrong. For the average realist this sounds nearly trivial. He would even think that true theories must be successful whereas false theories must fail.
But alas! this is not the case. It might happen that a theory is wrong, but doesn't fail. But if it fails it cannot be true. It is simple logic which is used here: If the premises are true and all deductive steps are correct, then the conclusion is true as well. We may therefore say: In correct deductions truth is hereditary. That's why logic is so important for science: It gives a conditional warranty: If premises are true (and all deductions are correct), then conclusions are true as well. Unfortunately this does not apply in the opposite direction: If conclusions are true, this does not imply that all premises must be true. Or in the language of the scientist: If the predictions derived from my hypotheses turn out to be correct, this does not mean that these hypotheses are true. That's a pity, but we cannot help.Fortunately we have another warranty: If conclusions are wrong (although all deductions are correct), then at least one of the premises must be wrong. That's the simple reason why we can never prove a theory, but may manage to falsify it.
We may deplore that we cannot prove our theories, but we should be happy that we can at least falsify them. Thus we can learn which ideas, concepts, speculations, hypotheses, models, theories don't work. Falsifications improve our knowledge. Even if we don't know which theory is true, we at least know of some theories that they are not true. We learn from our mistakes. This led to the saying: „I learned so much from my mistakes. I think I should make even more mistakes.“ A colleague of mine, Odo Marquard, put it in an even shorter formula: „We err upwords.“
Why was this simple insight so long neglected? Why did Putnam, van Fraassen and most other realists put up with the success of realistic hypotheses, theories and so on instead of referring to their failure? Again the answer is simple enough: They would say that they are interested in truth, not in falsehood.
That‘s honorable. But the argument for realism would be valid even if up to now no theory had been successful. For the realist this would mean that up to now none of his theories was right (or true) and that he should try again with new hypotheses. He might despair and abandon every hope. But he could still say that all his approaches were wrong, false, untrue, and that this was the reason why they failed.Thus the realist has at least an explanation why his approaches failed. Whereupon the antirealist has no answer to the question why his approaches failed. He might invent new words for describing his failure: He might say that it went awkward or haywire; he might just confess that he was unsuccessful. But all these formulations are descriptive, not explanatory. I had this experience several times when I asked constructivists why some of their approaches failed. They could not answer this causal question, but only translate their description into other words. But a simple translation is of course no explanation.
Again this does not mean that realism is proved by the failure of realistic theories. That realism explains the failure of theories is a good argument, but not a proof. And it is a better argument than the success of science because, as we said, even false theories might be successful. The advantage of realism over antirealism is not provability, but explanatory power.
In normal teaching, we are not told that the history of science is full of false theories. For good reasons we are taught only theories which are accepted as true. The reason is simple: There is no time to teach and to learn—beyond the theories we accept—also some of the theories we reject. There is one advantage: We don't waste time in learning things we don't really need. But there are also several disadvantages of not learning about the many false theories:
• We don't learn how difficult it was to find the truth.
• We don't learn how easy it is to make mistakes.
• We don‘t learn how many false theories were created before the good ones were found.
• We don't learn that even the most admired heroes of science made a lot of mistakes and to use this as a consolation and as an encouragement to try again.
• We erroneously conclude that our predecessors were naive or even stupid. What then will our followers think about us?
• We don't learn that we should not be ashamed of having made mistakes and of still making more of them. (But we should take into account that we may make mistakes and try to find and to eliminate them. The search for mistakes is one way of making progress.)
• We tend to distrust realism instead of taking the failures of our theories as confirmations of realism.
Regarding all this we see that thinking about realism and considering arguments for and against realism has not only theoretical consequences, but is also of practical value in learning and teaching. To put it in an aphorism: The more theories are exposed as wrong, the better confirmed is realism!
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