When it comes to aliens, Yeti and God, forget science

PETER MEDAWAR, the British immunologist and 1960 Nobel Laureate, described science as “incomparably the most successful enterprise human beings have ever engaged upon”. Over the past 400 years science has discovered the most amazing knowledge about how the natural world works and applications of this knowledge in the form of science-based technology now underpin our entire civilisation. All of this power comes from the repeated application of the methods science uses to investigate the world. This is discussed by Michael Shermer in July’s Scientific American.

Basically, the most common form of the scientific method works as follows. You wish to explain some part of the natural world that presently is unexplained. First you study all that is known about this phenomenon. Then you formulate your best informed guess, called a hypothesis, as to how this phenomenon works. You then make a prediction about the phenomenon, based on your hypothesis, and you check to see if your prediction works out – an experiment. If the experiment supports your hypothesis, you devise further predictions and test them by experiment. You continue this process over a long time and, if your hypothesis continues to be supported by experiment, you eventually begin to have confidence that your explanation of the phenomenon is correct. However, if several experiments fail to support your hypothesis you must think again.

Basically, the method is both sceptical and statistical in nature. It is sceptical because you assume in advance that your hypothesis is wrong until proven right, and statistical because you only accept support from an experiment after repeating the experiment many times until you can have at least 95 per cent confidence that the result you are getting is reliable.

However, not all aspects of the natural world are amenable to investigation by the form of the scientific method just described. For example, phenomena and processes that have developed over historical time, such as the origin and evolution of life or the origin and evolution of the universe, must be investigated in a different manner. Here you must use numerous lines of enquiry, and conclusions can only be drawn after these converge to produce an unmistakeable conclusion. Thus, the theory of evolution through natural selection rests on the converging evidence of the history of life on earth gleaned from palaeontology, geology, zoology, botany, comparative anatomy, biogeography, molecular genetics, physiology, and so on.

Science relies on hard evidence and will accept nothing as true until it is validated. For example, science will not accept the validity of UFOs because the supporting evidence is so flimsy. But, if alien spacecraft physically and unambiguously appear tomorrow, science will accept them as real. The same holds for the Abominable Snowman and the Lough Ness Monster.

But what about God? Well, God by definition, is supernatural and cannot, in principle, be investigated by science, which deals exclusively with the natural world. The generally accepted position is that science neither affirms nor denies the existence of God, it is simply silent on the matter. Some scientists, of course, do not agree with this position, notably Richard Dawkins.

Some secondary phenomena that can derive from belief in God, such as claims for the efficacy of intercessory prayer, can legitimately be tested by science. I think it is fair to say that the most rigorous scientific studies of prayer find no positive effects. Claims of “miraculous” cures at shrines such as Lourdes could also be amenable to scientific investigation. I understand that such “cures” are carefully investigated and that some cures defy conventional medical explanation. But, because something isn’t understood by science doesn’t mean that it has a supernatural explanation. History is full of examples of phenomena inexplicable to science and attributed to supernatural causes that later were quite adequately attributed to natural causes. The “intelligent design” found in nature by William Paley (1743 – 1805) and attributed to the handiwork of the Creator, was later shown to arise naturally by the process of natural selection.

There is much that science still cannot explain, such as what existed before our universe began, but science is justifiably confident that all these questions will yield in due course to the scientific method.

William Reville is associate professor of biochemistry and public awareness of science officer at UCC