THE Austrian zoologist Konrad Lorenz had some shrewd advice about getting ahead in science. 鈥淚t is a good morning exercise for a research scientist to discard a pet hypothesis every day before breakfast,鈥� he suggested. 鈥淚t keeps him young.鈥�
This will resonate with many researchers, but it might come as a shock to non-scientists, who tend to see science as a conservative process and scientists as conventional. Science is often portrayed as a discipline of certainties, its only currency indisputable facts. The reality is, of course, far more complicated.
To help put the record straight and to show scientists as the radicals they really are, I decided to write a book that explores the dramatic history of the big bang model of the universe. I wanted to use it as an example of how science works at its rebellious best. Who came up with this revolutionary idea and why? How did the big bang model transform itself from a maverick hypothesis on the fringes of science into part of the scientific establishment?
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The evolution of the big bang model is the story of a classic paradigm shift 鈥� a radical change from one view of the world to another. Initially, the scientific establishment believed in an eternal universe. Then in 1927 the Belgian cosmologist Georges Lema卯tre followed Lorenz鈥檚 advice and discarded that hypothesis before his breakfast waffles. In its place he proposed a moment of creation 鈥� 鈥渁 day without a yesterday鈥�. He found his colleagues distinctly unimpressed. Even the notoriously open-minded Albert Einstein told Lema卯tre, 鈥淵our calculations are correct, but your physics is abominable.鈥�
The big bang theory received some support in 1929, when Edwin Hubble showed that the galaxies were receding at speeds proportional to their distance, which is exactly what the model predicted. Nevertheless, the establishment demanded more evidence. They got it, eventually. Over the next four decades, a series of major discoveries began to persuade sceptical scientists that the big bang might actually have happened. It became more and more convincing: as well as explaining the motion of the galaxies, the new model accounted for other features such as the amount of helium in the universe, the distribution of the galaxies, and the existence of microwaves throughout the universe.
鈥淭he scientific method is largely a mystery to most people 鈥� and this is worrying鈥�
This was a haphazard evolution. During those four decades of uncertainty, the debate centred not so much on the scientific evidence 鈥� which was weak 鈥� but on people鈥檚 personal aesthetic, philosophical or religious convictions. For example, Pope Pius XII supported the big bang theory because it hinted at a creator. Atheists, including the Soviet establishment, criticised it for the same reason. However, as soon as the crucial observations emerged, a more objective consensus won through and the paradigm shift was complete.
None of this will surprise working scientists. For them, the mechanism by which disputed territory at the frontiers of their subjects is transformed into certainty in the heartlands is thoroughly ingrained; they do not require lessons in the scientific method. As the physicist Richard Feynman once said: 鈥淧hilosophy of science is about as useful to scientists as ornithology is to birds.鈥�
But the scientific method is largely a mystery to most people 鈥� and this is worrying. Every day we are confronted by news stories that involve science, from health issues to climate change. People need to understand how science works if they are to discern whether a news headline reflects a proven scientific certainty, a strong scientific probability, a mere scientific possibility, or a vague conjecture for which there is very little evidence at all. Only then can they make informed decisions about whether to take a particular vaccine or endorse a political stance on global warming 鈥� or wait for more research.
How do we encourage a wider understanding of the scientific method? One solution is to have children study paradigm shifts as part of their basic scientific education. At age 11, they might learn about the Copernican revolution; at 12, the story of Charles Darwin; at 13, they might study how geologists proposed the theory of tectonic plates; at 14 the rise of the big bang model. And at 15 they might explore an example with a direct impact on their lives, such as how scientists changed their understanding of CFCs from inert compounds to ones that jeopardised the environment.
They would then leave school with a good understanding of the scientific method and its principles 鈥� such as the central idea that theories have to be backed up by observations or experiments or they must be discarded. It does not matter how beautiful a theory is or how much scientists want it to be true: matching reality is the ultimate test. I would be satisfied if students left school with a full appreciation of just one simple sentence 鈥� Thomas Huxley鈥檚 elegant statement: 鈥淭he great tragedy of science: the slaying of a beautiful hypothesis by an ugly fact.鈥�