September 2009 – By Professor William Reville, University College Cork
Peter Medawar the British immunologist and 1960 Nobel Laureate for Physiology or Medicine memorably 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. And all of this power comes from the repeated application of the method science uses to investigate the world. This is nicely discussed by Michael Shermer in Scientific American, July, 2009.
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 to date 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 – this is called an experiment. If the experiment supports your hypothesis, you devise further predictions based on your hypothesis 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 reject your hypothesis and 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% confidence that the result you are getting is reliable i.e. there is only a 5%, or less, probability the result is simply due to chance.
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 firm conclusions can only be drawn after these multiple lines of enquiry converge to produce an unmistakeable conclusion. Thus, the theory of evolution through natural selection rests on the converging evidences of the history of life on earth gleaned from palaeontology, geology, zoology, botany, comparative anatomy, biogeography, molecular genetics, physiology, and so on. Explanations furnished by this method are just as sound as the explanations furnished by the hypothesis/experiment method already described.
Science relies on hard evidence and will accept nothing as true until it is validated by the scientific method. For example science will not accept the validity of UFOs because the supporting evidence is so flimsy – fuzzy pictures etc. But, if alien spacecraft and alien beings physically and unambiguously appear tomorrow, science will accept them as real. The same holds for the Abominable Snowman, Lough Ness Monster, and so on.
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. So, most scientists treat the God question separately from other claims such as aliens etc. The generally accepted position is that science neither affirms nor denies the existence of God, it is simply silent on the matter. Of course I am well aware that some scientists do not agree with this position, notably Richard Dawkins.
Of course, 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 medically 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 by science. For example, the ‘intelligent design’ found in nature by natural theologian William Paley (1743 – 1805) and attributed to the handiwork of the Creator was later shown to arise naturally by the process of natural selection discovered by Charles Darwin and Alfred Wallace in 1859.
There is much that science still cannot explain, such as what existed before our universe began, how life spontaneously arose on earth, and much more. Science is justifiably confident that all these questions will yield in due course to the scientific method.
(This article first appeared in The Irish Times on 3rd September, 2009.)