It is often said that science is just a collection of ‘facts’, but this is to misunderstand both what science is about and the scientific method. To a scientist, all ‘facts’ are provisional and may prove to be wrong if new information comes to light. What it really means is that it is the best explanation that has been found so far and explains the known situation better than any previous explanation.

A common misunderstanding about science is the nature of ‘a theory’. Theory actually has two meanings. Firstly it is an explanation for some happening or situation, that has been worked out, provisionally, to explain it. A scientist will come up with a provisional theory to explain something s/he has discovered. This ‘theory’ is then tested, by the originator and others, to see how good it is in explaining the known facts about the situation. Everyone, including the originator, tries to prove it wrong: It is tested to destruction. As this happens, the first type of theory is converted into the second type. That is, it becomes an accepted explanation for the facts.

The first type of theory is often referred to as a ‘hypothesis’ and the second type as a ‘fact’ to distinguish between them. The two types of theory are often confused, either accidentally or deliberately, by critics of science, who want to promote their own worldview. For instance, creationists refer to Darwinian evolution as ‘just a theory’ inferring that it is the first kind of theory and still an unproven hypothesis, when in reality it is the second kind, and accepted by scientists as an adequately proven fact.

Usually, the proposer of a new theory will have tested it as much as possible before publishing it and allowing others to try to disprove it. It’s better to find one’s own errors than have them pointed out by other people! These attempts to disprove a theory are an important part of the scientific method in which an hypothesis is tested thoroughly before becoming accepted as a fact and hence part of the knowledge base of science. Later findings will usually only help to refine the theory.

However, sometimes a revolution occurs and a theory will be overthrown and replaced with something better. For instance Newton explained gravity as being an attractive force between bodies. Einstein changed all that by showing that it is a feature of curved space-time. But gravity still works the same, it is only the explanation of how it works that has changed. These revolutions are not always easily accepted and the promoters of a new theory must often fight for its survival. Scientists, being human after all, are not always happy when their favourite theory is discarded. However, if the evidence supports it, the new theory usually, eventually, takes over from the old one.

Of course, science is not perfect – nothing created by humans can be. It does make mistakes. An example is the Phlogiston Theory. For some time, Phlogiston was thought to be a gas with a negative weight, which was used to explain combustion. The explanation was eventually shown to be wrong when combustion was investigated in more detail. Science is one of the few fields which actively protects itself from its own mistakes.

Critics of science make much of this changeability of scientific explanation to discredit science and its methods. They argue that science is never sure of anything so its explanations are not to be trusted. In reality, it is one of the most important features of science, and one that makes it so valuable. Few other fields of human endeavour will admit that they are wrong, throw away their mistakes, and replace them with something better. That way progress is made. Unlike religions, science never claims to provide the infallible truth. Every explanation is dependent on the current state of knowledge, and that will probably, almost certainly will, change.

The scientific method then involves working out an explanation of a phenomenon and then testing the explanation, finding its shortcomings, and revising the explanation until it is as near perfect as humanly possible, and then encouraging other people to try to find a flaw that proves it inadequate and replacing it with something better. Thus scientific theories evolve – the good ones survive and lead to better ones, the bad ones disappear into history. Perfection may never be reached, but it is aimed for and approached ever more closely. At the centre of the scientific method is the principle of never accepting anything as proven beyond all possible doubt. All explanations are provisional on the knowledge we have at present. A new discovery tomorrow might give new evidence that casts doubt on them. The important point is to keep asking questions.

However, the provisional nature of scientific explanations does not make them wrong. It just means that they are the best explanation found so far. Many of these explanations have been tested to the point where no scientist expects them to be ever proven completely wrong, although new information may require some slight modification in the details. Even then, it is most likely to be some minor point that would not affect its application in everyday life. Once a theory reaches this stage of its existence it will have been thoroughly tested in many situations. It can be taken, for all practical and theoretical purposes, as a proven fact and almost certainly will not be proven wrong. That ‘almost’ is important to science, because it means that the certainty is not absolute and never will be, because knowledge, being a human occupation, can also never be absolute. Science, unlike religions, does not deal in absolutes.

Science encourages us to question everything, even earlier theories, to find out if they are right or wrong. That is different from many other systems of thought, such as religion, which disapproves of its dogma being questioned. Questioning everything is a good way to find new things that have not previously been explained. It is also a good approach to life, since there are many sources, such as propaganda and advertising, which try to control our thoughts and make us react unthinkingly for the wrong reasons.

The scientific method is important because it stops us seeing the world as we want it to be and makes us see the world as it really is. The scientific view is objective and opposes our usually subjective view of the world. It is the search for better explanations that makes the scientific method so valuable and it means that our understanding of the universe and life, and our place as part of it, is always growing.

All children should be taught the scientific method as an important part of their education. It will teach them to distinguish between fact and fiction and to avoid being convinced by spurious arguments that have no rational basis.