The really impressive thing about science is that it works. This induces such faith in science that everyday we trustingly put our lives in the hands of science-based technology, for example by taking aeroplane flights.
Science produces satisfactory and globally accepted answers to the questions it asks. This does not apply in other areas, such as religion and politics, which has led some people to claim that the scientific method is the only path to truth. However, various philosophers have questioned the ability of the scientific method to unmask the truth, while some sociologists claim that scientific knowledge is constructed by social consensus.
I believe that the scientific method has proved itself capable of producing reliable maps of the physical world. The method does not produce the truth pure and simple, but we can be sure that it at least produces reliable information about the nature of the physical world.
A map can only tell so much about the terrain it represents. The scale of the map is a representation of the level of detail that it contains - the larger the scale the greater the information.
As science progresses maps showing ever finer detail are drawn. Ongoing investigations also sometimes call for revisions to be made to the map. For example, Einstein's insight into the physical world produced a map at a finer level of detail than the map drawn by Newton. On the other hand, the genetic understanding of Darwin's theory of evolution called for a radical revision of the map drawn by Lamarck which suggested that offspring could inherit characteristics acquired by their parents during the parents' lifetimes.
There are several reasons why the scientific method cannot produce the truth with absolute certainty. One is induction, the logical process on which much of science depends. Consider the case where the behaviour of some phenomenon is noted. Every time the phenomenon is observed it behaves in that way, and everyone who observes the phenomenon sees it happening in the same way, and it happens in this way under all sorts of circumstances.
AFTER many such observations science feels confident in making the assertion that this phenomenon has such-and-such properties. This is induction and it has been used to establish many things in science, such as the laws of planetary motion. Yet, because something has always behaved in a certain way in the past one cannot logically conclude that it must happen that way in the future. I'll grant you that this is a minor qualification of the validity of scientific conclusions, but it is sufficient to deny the award of absolute certainty to science.
Bertrand Russell gave a grisly illustration of the dangers lurking in induction. A farmer fed a turkey every morning at 9 a.m. The turkey drew up a law stating: "The turkey is fed daily at 9 a.m." This law held true until Christmas Eve, when the turkey ended up on the dinner table.
The Austrian philosopher Karl Popper took the position that if the inductive process can never absolutely prove that something is true, then science should use a process that allows it to at least know for sure when something is wrong. He proposed that science progresses by making proposals (hypotheses) as to the nature of a phenomenon, making predictions based on these hypotheses and testing these predictions by experiment.
If the prediction passes the test the hypothesis is provisionally accepted and further tests are devised. If the prediction fails the test the hypothesis is rejected and a new hypothesis is formulated. A hypothesis that is not refutable cannot be regarded as scientific.
A hypothesis that continues to pass every test gradually becomes more and more accepted as representing the true explanation of the phenomenon. Popper's proposal resonates with most scientists as representing a large part of the way in which science progresses.
Some sociologists believe that science is determined by social factors rather than objective criteria. This interpretation would hold that Darwin's theory of evolution, often summarised as "the survival of the fittest", was introduced to harmonise with the rise of capitalism, a system in which the strong out-compete the weak.
No scientist could accept that science is socially constructed. Experiments often produce results at odds with one's expectations and intuitions. When this happens you must adjust your ideas to fit the experimental data. The organisation of the natural world is completely unaffected by human hopes, intuitions and preconceptions and only the scientific method can efficiently uncover nature's secrets.
Science is not immune to social influences, however these influences affect but do not effect science. For example, scientific research is expensive and must be funded. At any particular time certain topics are popular with funding agencies and others are not. At the moment the Irish Government is targeting biotechnology and information technology for big support.
Also from time-to-time social prejudices unconsciously affect science, as happened when early 19th century microscopists investigated the fine details of procreation. Society then did not accord women nearly the same status as men and it was assumed that the woman's role in the process was that of the nurturing seed planted by the man.
When the microscopists examined sperm they "saw" a pre-formed human, which they called the homunculus. They concluded that these beings developed within the womb over a nine-month period and then emerged as babies. Later work showed that the homunculus was an optical artefact. When examining the sperm, the microscopists were seeing what they wanted to see.
William Reville is a senior lecturer in biochemistry and director of microscopy