What Can we Predict? -|- Educational Philosophy Theory

What Can we Predict?

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Popper’s insistence that all conclusions must be drawn by deduction, then, is at variance with the reality of scientific practice. Indeed, those areas of science—like certain branches of particle physics and cosmology—which have developed an excessive dependence on the method of deduction and abstract reasoning, are getting into a deeper and deeper mess. Nor is the business of the testing of a new hypothesis as straightforward as Popper makes out. There are many theories which are in daily use, despite the fact that they are known to be quite inadequate, for the simple reason that they are the best available; an example is Hooke’s law, used by engineers to check the relationship between stresses and strains in a material.

In a very perceptive article (unfortunately unsigned) published in the Science section of The Economist in December 1981, Popper’s views on science are exposed to a searching analysis, with quite devastating results:

"There are a lot of experiments where you cannot restrict the results to yes-or-no answers or where it is extremely hard to interpret what the answers are, because of the so-called signal-to-noise ratio. Suppose you repeat an experiment six times and get the result you predicted only twice. Does that prove the prediction was wrong? Or that four times out of six you failed to get the experiment right? In biology, such results are common: the vagaries of nature are notorious.

"While scientists strive for unambiguous answers, often they have to settle for less. And even if you do get results that unambiguously show the prediction of a theory is wrong, it is still not always clear what you have falsified. Strictly speaking, testing an isolated hypothesis is impossible. Consciously or unconsciously, the scientist assumes much else from the pyramid of knowledge besides the hypothesis tested." (The Economist, December 26th 1981, p. 101.)

The emphasis on prediction as a necessary precondition of the scientific method has been greatly exaggerated, and does not conform in the slightest to the reality of science. An astronomer can sometimes predict the position of a star many millions of years hence. But Darwin could not predict what species would evolve in a million years’ time. Geologists cannot predict precisely the time and place of an earthquake. And with meteorologists, the situation is still more hopeless. Even with all the armoury of modern computers and satellite technology behind them, they can only predict the weather with any degree of accuracy for a maximum of three days. Incidentally, even astronomy is not such an exact science as used to be thought. There are plenty of unpredictable phenomena in cosmology, yet no-one in their right mind would deny that astronomy is a science because it is unable to predict precisely where the next star will be born.

The reality of science certainly does involve making predictions to test out theories, although the nature of the prediction and the type of experimental "test" will vary enormously from laboratory test tubes to vast astronomical distances. Just because some predictions are not, and cannot be made, does not rule out the idea as a scientific method. There are sciences and sciences, and there are predictions and predictions. Predictions involving simple linear systems can be made with a high degree of certainty. But complex systems are difficult, or impossible to predict with any degree of accuracy.

For all the satellites and computers, it is impossible to predict the weather accurately more than three days in advance. Is meteorology a science, or not? Earthquakes cannot be predicted, and there are no neat laboratory experiments to prove the theories of geology. Is the latter a science, or is it not? And what about the predictions of a doctor? Even the best doctors make mistaken diagnoses, sometimes with fatal results. Is medicine a science? Clearly, it is, but not a precise science like some branches of physics.

When we reach a field like psychology, things get even more complicated. Psychology, as a science, is still in its infancy. One cannot yet speak of a fully worked-out body of ideas which is generally accepted in this most complex field, involving the basic driving-forces of human behaviour. And when we come to sociology, which, after all, deals with the complex behaviour of masses, the huge amount of variables makes the task of prediction doubly difficult. Difficult, yes. Impossible, no. For in human society also there are certain patterns of behaviour, certain processes, which can be identified and explained. General conclusions can be drawn, and, yes, predictions made, which can be tested in practice. Only don’t expect the same precise degree of accuracy in such predictions as you would hope to find in a carefully-conducted laboratory experiment!

At best, it is possible to predict the most general tendencies in society, and even these predictions must be constantly revised, added to and modified in the light of experience. In the end, they may be falsified by events, for a number of reasons, just as a even the best doctor’s diagnosis may turn out to be wrong. Does the doctor then draw the conclusion that diagnosis in general is an unscientific occupation, a waste of time? Or does he go back and try to discover the source of his error, in order to learn from it? The real question that should be asked is: Do we believe that it is possible to obtain a rational understanding of the laws that govern social evolution? If the answer is no, then all further discussion is pointless. If human history is seen as an essentially meaningless string of accidents, then there is no point in trying to understand it. But if science has succeeded in discovering the laws which governed the development of humankind in the remote past, based on the extremely scanty evidence of a few precious fossils, then it is not at all obvious why it should be impossible to uncover the laws which determined the evolution of our species for the last 10,000 years. Yet this is declared out of bounds by Professor Popper. All who attempt to do this will be immediately be condemned for the heinous crime of historicism.

Thus, we are entitled to ask about the far-flung galaxies, and the smallest particles of matter, but if we attempt to arrive at a rational understanding of society, of history—that is to say of ourselves, who we are and where we came from—that is not allowed. The arbitrary nature of this prohibition is so glaring that one cannot avoid asking what the reason for it is. Is it really to do with science? Or might it have more to do with certain vested interests which do not want people to ask too many questions about the past and present of the type of society in which we live, for fear that they might draw all the wrong conclusions about the type of society we would like to live in in the future.

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