Jennifer Marohasy

“THE scientific method is a valuable way to advance objective knowledge. By testing a hypothesis against observation, it can either be falsified or supported. Not proved, of course, but nevertheless over time sufficient evidence can accumulate for a hypothesis to be generally accepted as the best available explanation. It is then known as a theory. Hence, although the vast majority of scientists and citizens (at least in Europe) accept Darwin’s description of evolution, this is still regarded as a theory rather than fact. This is important, because as our understanding develops, apparently satisfactory theories may be replaced by others.

For simple things such as the effect of the Earth’s gravity on objects we are familiar with, collecting the evidence is straightforward and no experiments have been done which contradict the theory of gravity. But over the last century, it has been accepted that classical Newtonian mechanics is actually only valid at a certain scale (which encompasses everything in our normal Earthbound existence). At the atomic scale, we enter the abstruse realm of quantum mechanics, and on a cosmic scale Einstein’s theory of relativity is currently the best description of what goes on across the observable universe.

Importantly, both of these deviations from the familiar everyday world as explained by Newton arose because observation did not fit with prediction: the theory broke down at very large and very small scales. The boundaries of knowledge have since been pushed back steadily, leading to a general acceptance of quantum mechanics and relativity as the best theories to date to explain observations.

On a cosmic level, there is still much we do not know. It is now generally accepted that the Big Bang theory describes the universe better than the previously-competing Steady State model. But current models require the universe to be composed largely of as-yet-undetected “dark matter” and “dark energy” if observations are to be consistent with theory. And on a broader scale, the search for a “theory of everything” which brings together quantum mechanics and relativity and explains gravity remains unresolved, with the large amount of work on the development of string theory potentially being a historical dead end…

This sort of work engenders fierce scientific rivalries, and the formation of a consensus view can take many years, but it is essentially an internal professional competition, of little direct relevance to the average citizen (apart from the fact that their taxes pay for it). However, when we come to issues which affect non-scientists more directly, other interest groups become more involved…

But when we turn to environmental issues, the situation becomes more complex still. To test a hypothesis, it is always best if only one independent variable can be changed at a time. In the laboratory, this is usually possible, but when hypotheses have to be tested purely by observation of highly complex systems, life gets much more difficult. And it is difficult to think of something much more complex than global climate.

It is well known that there were serious concerns raised about climate change in the 1970s, although at that time the worry was about cooling and descent into a new Ice Age. However, attention soon turned instead to global warming. A sudden jump in temperature in the mid-1970s was followed by an upward trend over the next two decades, and it was perfectly logical to hypothesise that this increase was caused by rising levels of carbon dioxide in the atmosphere.

This quickly became the new paradigm, linking humankind’s burning of fossil fuels directly to environmental change on a global scale. Unfortunately for the cause of rational debate, this also quickly became the only acceptable hypothesis for large swathes of the scientific community, pretty much everyone who considered themselves an environmentalist and the liberal elites in Western democracies…

Read more here.

************************

Scientific Alliance newsletter 12th June 2009
Science, belief and rational debate by Andy Hooper
http://www.cambridgenetwork.co.uk/news/article/default.aspx?objid=60280