|Dr Julian Baggini|
philosopher, editor of the Philosophers' Magazine, and columnist at Butterflies and Wheels
The underdetermination of theory by evidence
One of the greatest obstacles to scientific understanding is the misconception of what is meant by proof and evidence. Many people seem to think that science should be able to prove its hypotheses with 100 per cent certainty, and that anything less means that you cannot be sure. Some would go so far as to say that this means everything is just a matter of faith or opinion.
If people understood the general principle of the underdetermination of theory by evidence, then I think they would understand many specific scientific claims more clearly. This principle basically explains why it is that the evidence can never demonstrate that one and only theory must be true. This is only a problem if you have unrealistic expectations for what science can do. For a realist, the principle of the underdetermination of theory by evidence merely shows why science is, of its nature, fallible. But that does not mean that science is not an excellent method nevertheless.
And in the absence of proof, some explanations are clearly far preferable to others. Widespread scepticism about evolution, for example, would not be possible, if people fully appreciated the underdetermination of theory by evidence. Nor would people find conspiracy theories as attractive as they do, if they appreciated that an explanation can fit the facts perfectly, yet still be complete nonsense.
Julian Baggini is author of books including The Pig That Wants to Be Eaten and 99 Other Thought Experiments (buy this book from Amazon (UK)), and What's It All About?: Philosophy and the Meaning of Life (buy this book from Amazon (UK)). See his website.