History and Historiography of Science

SEE Q&A (6): Science, Policy, and Certainty

We continue our 8-part Q&A with Harry Collins and Rob Evans concerning their Sociology of Expertise and Experience project.  Once again, we note that Collins and Evans crafted their answers jointly.  This is not a spontaneous exchange.

Will Thomas: You begin the introduction to your book with the statement: “Science, if it can deliver truth, cannot deliver it at the speed of politics.”  The statement implies certain things about the nature of politics and the nature of science, particularly that politics seeks action where science seeks certainty (i.e. “truth”).  Yet, as Jasanoff has pointed out (say, in her “EPA” piece in the 1992 Osiris), it is politics that demands certainty of science, not science itself.  Science, absent a political imperative, tends to be used for the production of more science, rather than the production of solid claims.  Does science have a tolerance for uncertainty that politics does not?  Can science make legitimate decisions quickly if certainty may be discarded?  Does politics demand certainty (or at least the appearance of it) when taking action?  If not, what constitutes the requirements of a legitimate political decision?

Harry Collins and Rob Evans: It is not correct to say that science does not demand certainty of itself.  Thus Collins has spent decades immersed in the gravitational wave detection community and found it to be a community that is obsessed with the certainty of the results.  Collins often finds himself arguing with members of that community because of their hostility to the publication of any finding that is tentative—an argument described more systematically in Gravity’s Shadow as a tension between evidential individualism and evidential collectivism.  Most of the scientists in that field would agree that, unless something remarkable happens, even the first widely accepted published claim to have directly seen the influence of a gravitational wave on a terrestrial detector will not be believed until it has been backed up by many other observations.  If one thinks about what is distinctive about the form of life of science then the reach for certainty is central.

But part of the notion of certainty is certainty about how certain something is.  The defining feature of quantum theory, which is often claimed to be the most accurately predictive theory of science there has ever been, is that its certainties are cast in terms of probabilities.  And that will be true even of the first claim to have seen a gravitational wave—it will be expressed as a probability—‘n’ sigma.  Even in the social sciences we prefer a three-sigma result to a two-sigma result because it is more likely to be correct.

Of course, sciences differ in their ability to deliver certainty.  In the physical sciences it can take a long time to reach what is acceptable as ‘a conclusion.’ Experimentally demonstrating the constancy of the speed of light to everyone’s satisfaction took about 40 years and the gravitational wave community will have spent about 50 years looking by the time they are ready to say they are sure they have seen a gravitational wave.  The matter is confounded in disputed areas because some scientists will be claiming that certainty has already been reached while others will be denying it.  This has been true of gravitational wave detection and was true of the constancy of the speed of light.

What Jasanoff is getting at is that a policy decision is a binary action—one either bans a certain chemical or one does not—that often does not coincide with core-set closure.  One cannot ban a chemical by 75%, or 99% or even just ‘probably’ or with an unknown degree of uncertainty.  The enigma of policy-making is converting measured probabilities, or even unmeasured probabilities, into binary decisions.  The problem gets harder to the extent that the speed of politics is faster than the speed of consensus formation.  In the case of the complicated science of the body, and that includes carcinogenicity, the uncertainties, and that includes unmeasured uncertainties, are likely to be with us for a long time.  What Jasanoff reveals in great detail is the attempt to evade political responsibility for what is always going to be an imperfectly justifiable decision.  The problem is how to legitimise an imperfectly justifiable decision and one way is to get scientists to take responsibility for it.

That this ‘pass the parcel of responsibility’ game can be found in politics is only due to the fact that the quest for certainty is not central to the form of life of politics.  What is central in politics is the quest for legitimacy.  In science people do not pass the responsibility for truth on to others, the whole ethos is about each individual trying to keep the responsibility to themselves.  One of the important findings of SSK is that the ability to keep the responsibility to oneself in science is mythical—one has to trust others but it is a grudging trust which scientists like to pretend is unnecessary.  SSK shows that in the practice of science the search for certainty is often the search for legitimacy but it does not show that the ‘formative intentions’ of a science include the search for legitimacy rather than certainty.  On the contrary, the difference between science and politics could be said to lie in that difference in their formative intentions.  (The term ‘formative intention’ is defined in Collins and Kusch’s Shape of Actions but the sentiment is not dissimilar from Wright-Mills’s ‘vocabularies of motive.’)

We would hope the ideas of the Third Wave would discourage the public from falling for politicians’ attempts to pass the parcel of responsibility for making the binary decision onto scientists at times when the science is too ill-formed to bear it.  The public can learn from Wave 3 that scientists can only give the best possible technical advice that is available and this may well be inconclusive or contested.  In the typical case in which science enters the public domain, the decision that follows such advice will and should be seen to be a political decision.  As for politicians, they have to accept that an analysis of advisors’ expertise is their best guide if they want to pick their way through competing voices and have at least some technical input into the decisions that remain their responsibility.