Ars Technica has an interesting post on how scientists themselves view the tentative nature of science. In ordinary language, a tentative conclusion is not to be preferred (the old “evolution is just a theory” canard), but in science it is in fact a virtue. Science’s conclusions are meant to be tentative, but a paradox is that as its conclusions are used and extended, that tentative nature tends to evaporate over time.
John Timmer asked a number of scientists how they viewed their data, their models and the broad theoretical frameworks. He got differing answers from different fields. Physicists and biochemists treated data as more tentative than the models in the light of which they were interpreted. But genomics researchers treated their data as high quality, and a neurobiologist insisted that the data in the field were messy, but not tentative.
In the case of models – which are explanatory schemes for a given phenomenon, either rough conceptual schemes or formal mathematical descriptions – all agreed they were tentative. A common theme was that “[i]f confirmed data disagrees [with a model], then the scope of the model becomes more limited or the model must be modified or discarded entirely at some level.” Interestingly and tellingly, biological models were regarded as restricted to the model organisms studied. I think this is due to the fact that generalisations in biology are based on historically contingent evolutionary sequences, and so the very next organism studied may have a divergent pattern from the previously studied ones.
What is most interesting is that theories, which form an intellectual framework for research and explanation, are regarded as much less tentative than models. For example (and this is my own example) natural selection was initially a rough model that became formalised by Fisher and Wright and subsequent theoreticians. It is now an established fact and broad theoretical framework in biology at all levels, although it is hardly the sole theory applied to all organisms. But even here, biology is something of an outlier, and theories are often abandoned or ignored, according to Timmer.
Engineering, which is the home of so many evolution deniers, is surprisingly also an outlier, in that major theoretical advances force major revisions every so often. Many engineering decisions are economic or political, though, and the chaos of development is masked by the final products and publications being so decisive.
Something Timmer alludes to but doesn’t explicitly say, is that very nature of science is to make progress by rebuilding itself; to use Neurath’s famous metaphor, much beloved of Popper, science is a boat being rebuilt at sea. Science learns by making conjectures, testing them, and occasionally abandoning them. Of course, it can’t do this is every piece of data or theory or model is up for grabs, so the teantive nature of data and models is not universal, nor should it be. Information and ideas that have served well for a long time, contributing to ongoing active and fruitful research will tend, properly, to be accepted. I am reminded of Hull’s interviews with evolutionary scientists:
Yet another ambiguity constantly crops up in our discussions of scientific theories. Are they hypotheses or facts? Can they be “proved”? Do scientists have the right to say that they “know” anything? While interviewing the scientists engaged in the controversies under investigation, I asked, “Do you think that science is provisional, that scientists have to be willing to reexamine any view that they hold if necessary?” All the scientists whom I interviewed responded affirmatively. Later, I asked, “Could evolutionary theory be false?” To this question I received three different answers. Most responded quite promptly that, no, it could not be false. Several opponents of the consensus then current responded that not only could it be false but also it was false. A very few smiled and asked me to clarify my question. “Yes, any scientific theory could be false in the abstract, but given the current state of knowledge, the basic axioms of evolutionary theory are likely to continue to stand up to investigation.”
Philosophers tend to object to such conceptual plasticity. So do scientists — when this plasticity works against them. Otherwise, they do not mind it at all. In fact, they get irritated when some pedant points it out. [David Hull Science as a Process, 1988, 7]