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About the Anniversary Address - 2005

The nature of scientific knowledge

The campaigns waged by those whose belief systems or commercial interests impel them to deny, or even misrepresent, the scientific facts are helped by the widespread public misapprehension that science essentially always gives unambiguous and definite answers. This misapprehension is both understandable and unfortunate.

Understandable, because the science taught in primary and secondary school, and also in much tertiary education, is about things we really understand very fully. This is, after all, the easiest way to organise curricula, and to set exam papers. Even more, the answers to "science" questions on TV quiz shows - University Challenge, Mastermind, The Weakest Link, and so on - cannot permit ambiguity and debate; here scientific understanding is misleadingly trivialised as definitions or nomenclature.

Unfortunate, because although much of science deals with things that are indeed extremely well understood, many of the topics that engage public attention lie at, or beyond, the frontiers of what is currently known. More generally, the landscape of scientific understanding is complex. At the ever-expanding frontiers, different ideas and opinions contend; the terrain is bumpy. But there are huge swathes of territory behind the frontier where evidence-based understanding has been securely achieved. For example, the Laws of Thermodynamics tell us assuredly that perpetual motion machines are impossible. In astonishing defiance of intuition, we now know that mass and energy can be interchanged, according to science's most celebrated formula, E = mc².

When AIDS was first recognised in the early-to-middle 1980s, various possible explanations contended; the landscape was one of many hillocks. Observation and experiment, however, fairly rapidly identified the virus HIV as the causative agent (helped by earlier "blue-skies" research on retroviruses). Although we as yet lack any agreed explanation for why there is so long and variable an interval between an individual becoming infected with HIV and coming down with AIDS, we do have an understanding - at the detailed molecular level - of how individual HIV viruses interact with individual immune system cells, and on this basis have been able to produce antiretroviral agents which keep HIV-infected people alive. By the same token, suggestions that the release of carbon dioxide by burning fossil fuel would cause greenhouse warming were made many decades ago. They were, however, beset with many uncertainties. The past two decades have seen great advances in acquiring observational and experimental data of many different kinds, and consequently in increasingly detailed computer models. But as the sciences of HIV/AIDS and of climate change have moved from their past positions at or beyond the frontiers of scientific understanding, into terra cognita which can provide a secure basis for effective action, there remain those who seek deliberately to confuse yesterday's uncertainty with today's fact-based understanding.

In this context, the Royal Society is pleased that the teaching of science at GCSE level will, from September 2006, concentrate more on improving young people's understanding of how science works, rather than on rote memorisation of uncontextualized definitions. That is, it will emphasise: collection, analysis and interpretation of data; the use of evidence to test ideas and develop theories; how explanations of many phenomena can be developed using scientific theories, models and ideas; and how there are some questions that science cannot currently answer, and even some questions that science cannot address. Young people should learn to have trust in science even when there may be uncertainty, scepticism in the face of propaganda purporting to be knowledge, and confidence that what we ask them all to learn is of value in their everyday lives.

More generally, we must of course recognise there is always a case for hearing alternative, even maverick, views. But we need to give sensible calibration to them. I could assemble half a dozen people (including one Nobel Laureate) who deny that HIV causes AIDS, and put them up against an equal number of researchers in this area. But unless I simultaneously gave some sense that the first six are a kind of travelling road-show, representing little beyond themselves, while the latter six could be chosen from among a hundred-thousand or more researchers in the field, I would, in effect, be misleading the public⁵⁰. The intention of "balance" is admittedly admirable, but this problem of wildly disparate "sides" being presented as if they were two evenly balanced sporting teams is endemic to radio, TV, print media, and even occasional Parliamentary Select Committees. England playing Australia is one thing; England playing the local village team is something else entirely.

These problems of effectively communicating what is known, and what is not, are further complicated, as noted above, when what really is at issue is a belief system masquerading as scientific scepticism, for example when Darwinian Evolution is questioned by Creationists disguised as proponents of the "alternative science of Intelligent Design" (ID). Broadly similar problems arise when a newspaper adopts an ex cathedra editorial position, as for example in the editorial line adopted by The Sunday Times in the 1990s that HIV does not cause AIDS.

Yet another kind of difficulty⁵¹ can be posed by those who emphasise "the constructed and value-laden character of scientific knowledge". Taken to extremes, this can lead to the view that scientific knowledge is no more than a "social construct", rather than statements about the external world, which in reality is (in Max Planck's words⁵²) "independent of our senses [with its laws] not invented by humans".

My personal belief is that important aspects of science, in the widest sense, are indeed laden with values; but we need carefully to parse out which aspects are, and which not. The inverse square law of gravity, for example, is value free. So are Maxwell's equations. These are plain facts, and any pretence to the contrary is silly. This is what Planck was talking about. The agenda of science, on the other hand, usually does reflect the values of particular times and places, although usually in implicit and unconscious ways. The fact that the inverse square law, itself based on centuries of observation of the motion of planetary bodies, came a full century before Linnaeus began the task of codifying the diversity of plants and animals that share our planet testifies eloquently to the vagaries of intellectual fashion that have shaped science's agenda. And the applications of our scientific knowledge bear the signature of social and political pressures even more strongly. For instance, recall Table 2, with its relative neglect of "unprofitable diseases". Or note that, whereas the earlier Green Revolution was largely born of public and charity money (especially the Rockefeller Foundation) and had an agenda oriented to consumers in the developing world, the first wave of applications of GM technology to crops was with private-sector money, and consequently directed mainly to agribusiness rather than nutritional deficiencies in the developing world.

In everything I have said above there is the implicit, but hugely important, assumption that the scientific community has an obligation to explain itself - its agenda, its achievements, and their potential applications - to the public. This means individual scientists engaging more with wider society, explaining what they do and why, and responding through dialogue and debate to the interests, concerns and aspirations of the public. Such engagement is not always easy, in part because it often requires simplifying things (usually painful to researchers for whom the details can be entrancing), and must always avoid distortion. This dialogue between researchers and the general public - or, more accurately, the many and varied "publics" - has in recent years been seen as an integral part of the scientific process. The UK has, I believe, been a leader in this, partly as the result of unfortunate earlier experiences (BSE in particular). The Royal Society hopes that, through its "Science in Society" programme and other activities, it has been creative in its exploration of such engagement.

Ultimately, as science advances our understanding of the external world, it offers us opportunities to improve life for all. However, as we increasingly come to recognise the unintended adverse consequences of well-intentioned actions (as seen above for climate change and for biodiversity loss), it behoves us to think more carefully about which doors to open and which to leave closed. In this task, the job of science is to frame the debate clearly, making plain the possible benefits and costs - and the concomitant uncertainty. And making clear that cloud cuckooland is not a feasible choice. But when it comes to acting out the democratic drama of choice on the stage thus set, science has no special voice; the drama of choice is about values and beliefs, about what kind of world we want.

Such choices, against a background framed by scientific facts and uncertainties, is hard enough. As emphasised earlier, it is more difficult when fundamentalist or other belief systems seek to blur the distinction between constraining facts and democratic decisions. We should keep in mind the cautionary tale of Indiana State, where in 1897 its Lower House voted to define the transcendental number pi (the ratio of a circle's circumference to its diameter) to be exactly 3.2 to make things easier for the construction industry; their Upper House saved embarrassment by vetoing the bill.