Wednesday, 1 September 2010

Why Beliefs Matter

A Matter of Faith

Why Beliefs Matter: Reflections on the nature of science by E. Brian Davies

New Scientist, 7 August 2010

Albert Einstein once asked, does the moon exist when no one is looking at it? Such questions had been the preserve of philosophers, but with the discovery of quantum mechanics in the 1920s they became legitimate queries for physicists, too.

Niels Bohr, one of the founders of quantum mechanics, did not believe that science grants us access to an objective reality and insisted that the task of physics was not to find out "how nature is" but only "what we can say about nature". Einstein, on the other hand, maintained an unshakeable belief in a reality that exists out there. Otherwise, he said, "I simply cannot see what it is that physics is meant to describe".

Einstein based his view of quantum mechanics on his belief in an independent reality - the moon does exist when no one is looking at it. In contrast, Bohr used the theory to construct and underpin his belief that the atomic realm has no independent reality. The two agreed on the equations but disagreed on what they meant.

"Scientists, like everyone else, have beliefs," writes distinguished mathematician E. Brian Davies in Why Beliefs Matter. He is not only referring to religious beliefs but to philosophical ones, too. While religious beliefs can be easy to leave at the laboratory door, philosophical beliefs are much harder to sideline.

Some mathematicians, for instance, subscribe to a Platonic view in which theorems are true statements about timeless entities that exist independent of human minds. Others believe that mathematics is a human enterprise invented to describe the regularities seen in nature. The very idea that nature has such regularities which render it comprehensible is itself a belief, as is the idea that the world we perceive is not some sort of delusion or practical joke.

The title of Davies's book, significantly, is a statement, not a question. For him, beliefs do matter. Davies offers a series of snapshots of how various philosophical views inform science, rather than a systematic inquiry into the nature of belief. Along the way he discusses the scientific revolution, the mind-body problem, machine intelligence, string theory and the multiverse. The result is a wide-ranging, thought-provoking meditation rather than a populist read. Beliefs, it seems, are a serious business, and they come in all shapes and sizes.

"At the highest level, beliefs become world views, fundamental beliefs that we use to evaluate other beliefs about the world," says Davies. World views can be evaluated, compared and changed, but you cannot avoid having one. Davies is a self-proclaimed pluralist. That is, he believes that humans have a limited mental capacity and will always need a multiplicity of ways of looking at the world in order to understand it. There may be two or more equally valid and complementary descriptions of the same phenomenon, he says - not unlike the concept of wave-particle duality in quantum mechanics. That does not mean that all world views are equally good - some simply don't hold up under the scrutiny of experiment.

The scientific revolution that began in the 16th century was a triumph of rationality and experiment over the superstition and speculation of the Middle Ages. Even so, nearly 40 per cent of Americans believe that God created humans some time within the last 10,000 years.

World views are not founded on logic, so the most that one can demand is that they should be consistent with what science has discovered. Yet, as the writer C. S. Lewis noted, some arguments are impossible to refute. "A belief in invisible cats cannot be logically disproved," he said, although it does "tell us a good deal about those who hold it".