Significance

There are two kinds of significance in science: statistical significance and conceptual significance.With the growth of computers, it is now much easier to carry out experiments and to calculate the data to assess statistical significance. This satisfies the career need to publish a large number of acceptable papers, and looks like `productivity'öbut is it? How much does a lot of statistically significant experiments advance science? After all, only some related events or trends or phenomena have significant interest. If the number of oranges grown in California correlates highly with the birth rate in a Welsh village, this is hardly a promising start or interesting conclusion for a PhD. However strong the statistical significance, some conceptual significance is needed for attracting interest. As computers are not noted for their thinking ability, knowledgeable intelligent humans are needed for assessing conceptual significance. It is up to us to think what an experiment means. Of course, we consider our own and our colleagues' findings; but thinking is a slow and difficult business, and, however hard-won, conclusions of years of thinking may be dismissed as mere `opinions'öso it is easier, and it often pays, to go for many statistically reliable experiments even if they do look pointless. Yet, aren't significant concepts the main point and excitement of science? Isn't it conceptual issues that dilate our pupils and expand the minds of our student pupils? This is only so for those who have caught the bug of science. Unfortunately, it applies hardly at all to the public. No doubt, the public want more efficient and cheaper vacuum cleaners, and why not? But how do such products of science compare with the power of concepts of scienceöappreciating how we evolved; where stars come from; how brains work; why we have consciousnessöto make living exciting? Surely the too widespread public distrust of science comes in large part from just what makes science worthwhile for scientists, who (in spite of such low salaries that old vacuum cleaners are hard to replace) see its uncertainties and disagreements as life-enhancing. In short: the controversies of conceptual significance which make science look unreliable to the public, are just what makes it so interesting for scientists. For the astronomer, it really matters that Continual Creation lost the argument against the Big Bang view of the creation and development of the universe. For the brain scientist, it really matters whether the brain is analogue or digital. And just remember the decade-long heat of battle over the significance of Fourier theories of vision. Here statistical significance of experiments was taken for granted; but they were far from sufficient to arouse interest, or charge debate with the excitement of the controversy of those years. Yet this, surely, is what breathes life into scienceömeanings of observations and experiments. When these are controversial, we get switched on and become creative. Of course, other things matter to scientists as to everyone else. A clean house is a pleasure, but puzzles of the vacuum of space (whatever happened to the Aether now that space is again supposed not to be empty? ) are much more exciting. Pleasures of many kinds are what life seems to be about, but for science we are happy to forego many obvious pleasures to seek significanceöconceptual significance. Statistically reliable experiments are a means to this, but they can be horrifically misleading without considered conceptual significance. The important point of statistical significance is to give convincing surprise, such that minds are changed. The greater the surprise, the more, in its technical sense, Editorial Perception, 2003, volume 32, pages 127 ^ 130