{"id":114819,"date":"2017-11-05T00:23:32","date_gmt":"2017-11-05T04:23:32","guid":{"rendered":"https:\/\/www.bu.edu\/sph\/?p=114819"},"modified":"2021-02-18T16:38:52","modified_gmt":"2021-02-18T21:38:52","slug":"how-do-we-know-when-we-know-something","status":"publish","type":"bu-article","link":"https:\/\/www.bu.edu\/sph\/news\/articles\/2017\/how-do-we-know-when-we-know-something\/","title":{"rendered":"How Do We Know When We Know Something?"},"content":{"rendered":"\n
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November 5, 2017<\/div>\n\t\t\n\t\t\t\t
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\"thisweek365-deans-note\"<\/p>\n

Before beginning today\u2019s note, an acknowledgement, once again, of recent tragedy. On Tuesday, New York City suffered\u00a0its deadliest terror attack since 9\/11<\/a>, when a man drove a truck into a pedestrian bike path, killing eight people and hospitalizing at least 11. Like recent attacks in Paris and Brussels, this incident appears to have been motivated by religious fanaticism and\u00a0hate<\/a>. The victims were from several countries, including\u00a0Belgium and Argentina<\/a>. This speaks to the international character of a city, my former home, that is proudly heterogeneous. Hopefully, this senseless act will catalyze a deeper appreciation of the cultural and religious\u00a0pluralism<\/a>\u00a0embodied by New York, at a time when\u00a0these values<\/a>\u00a0feel more vulnerable, and necessary, than ever.<\/p>\n

Moving on, with sadness, to today\u2019s note. Throughout my career, I have been struck by a phenomenon: Whenever I feel I have truly been immersed in a topic, when I feel like I know as much as there is to know about it, that is when I realize, inevitably, how much I do not know. This is, perhaps, akin to a broader observation about the generation of science. We are privileged to generate ideas for a living; one of the ways we pay for this privilege is by being keenly aware, perhaps more than most, of how little we actually know about many subjects. We are, for example, still studying the effect of marijuana legalization<\/a> on public health. We do not know nearly enough about the population health effect of firearms<\/a>, beyond the statistics<\/a> of death and injury with which we have become so familiar. The list goes on, and is long.<\/p>\n

But there are also areas where we do<\/em> know we are correct, and certainly know enough to inform action, even if we need to learn more around the edges. We do<\/em> know, for example, that climate change is real<\/a>, we do<\/em> know that vaccines are safe and effective<\/a>, we do<\/em> know that the theory of evolution is true<\/a>. Yet in each of these cases, politics has pushed back against the facts, making it harder for us to act on our knowledge. This pushback will often take the form of partisan actors saying that a given issue is still a matter of scientific debate<\/a>, manufacturing doubt<\/a> when the issue is, in fact, a settled matter. This can be exasperating for us, in the profession, to hear, but it also begs a useful question: When does \u201cthe preponderance of science\u201d tip the scales so we can definitively say \u201cwe know this?\u201d The better we can answer this, the better we can catalyze data-inspired action, and show why politically motivated efforts to distort science are dishonest and counterproductive.<\/p>\n

On achieving scientific consensus<\/h3>\n

It seems to me that the starting question needs to be: How do we define \u201cscientific consensus\u201d and decide, based on this consensus, that something is \u201ctrue”? In his classic book Science in Action: How to Follow Scientists and Engineers Through Society<\/em><\/a>, the sociologist and philosopher Bruno Latour introduces the concept of \u201cthe black box\u201d to represent a scientific conclusion that is widely accepted as true. The phrase is borrowed from cyberneticians. It is a kind of shorthand\u2014whenever a machine system or command set is unduly complex, a box may be drawn around it to indicate that all that is necessary to know is its input and output (Figure 1).<\/p>\n

\"Figure
Figure 1. Black Box \/ After Bruno Latour<\/strong>
Haunted Machines an Origin Story (Long). Occasional blog of Tobias Revell Web site. http:\/\/blog.tobiasrevell.com\/2015\/07\/haunted-machines-origin-story-long.html Accessed October 2, 2017.<\/figcaption><\/figure>\n

The box can still be \u201copened\u201d and the integrity of its contents examined, but marking it off in this way says that these components have already received ample scrutiny and been found to be sound. Latour relates this to science by using the example of the double helix. There was a time when no one knew for sure how DNA is structured (see, for example, the classic paper by Linus Pauling suggesting a triple helix<\/a>). It was only after<\/a> a rigorous process of scientific examination that the double helix shape came to be accepted and utilized as the basis for all further study of genetics. It is now a \u201cblack box.\u201d While this does not mean that the double helix shape cannot be questioned, implicit in the scientific consensus is the understanding that such questions would be a retracing of steps, rather than a forging of new paths. In this sense, what was once just theory has become accepted fact, achieving what Trevor Pinch and Wiebe Bijker have called<\/a> \u201cclosure.\u201d<\/p>\n

A more nuanced perspective offered by Uri Shwed and Peter Bearman suggests<\/a> three trajectories for scientific consensus. The first is a \u201cspiral\u201d trajectory, whereby \u201csubstantive questions are answered and revisited at a higher level.\u201d That is, we have reached consensus on the core issues and are now elaborating on nuance, with earlier, answered questions leading to new, unanswered ones. An example of this is our growing understanding of the link between income and health, one of the<\/a> most<\/a> widely accepted associations in our field. At core, the relationship between income and health is defined by factors like access to nutritious food<\/a>, quality education<\/a>, and health insurance<\/a>. With the basics of this link well-established, new research is moving our understanding of it to a higher level. We have begun to trace, for example<\/a>, the correlation between widening income gaps and widening health gaps in the US, and to examine how poverty, in particular, drives this inequality. Second is the \u201ccyclical\u201d trajectory, whereby \u201csimilar questions are revisited without stable closure.\u201d This is the trajectory of the salt debate, where the question of salt\u2019s effect on health is continually revisited, with closure not yet in reach. This poses a challenge, because while consensus may indeed be reachable, it nevertheless falls just beyond our grasp as we keep visiting and revisiting the same questions. The third trajectory is a \u201cflat\u201d trajectory, whereby \u201cthere is no real scientific contestation.\u201d That is: We know the answer, the question is closed, and argument may exist only to serve non-scientific ends. An example of this is the safety and effectiveness of vaccines, which is only contested by those employing bad science and roundly debunked arguments<\/a>.
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The challenges in getting to closure<\/h3>\n

Getting to \u201cclosure\u201d is, therefore, a process of iterative generation of science, whereby scientists eventually, through refutation, argument, and agreement, decide what is in the \u201cblack box.\u201d There are, as I see it, two impediments to this closure.<\/p>\n

The first arises when entrenched groups dig in on opposing sides of an issue, polarizing the debate. This polarization is not to be confused with the disagreement and exchange of ideas that are the lifeblood of any worthwhile scientific endeavor. Such an exchange depends on dialogue between people with different views testing what they think they know against the opposing views of others. Polarization occurs when this dialogue breaks down, and researchers confine their outreach only to those who share their perspective; this results in the classic \u201ccyclical trajectory\u201d noted earlier. To the point, in researching the debate over salt\u2019s effect on population health<\/a>, we found<\/a> that authors were 50 percent likelier to cite papers that shared their position on the subject. This creates a situation where consensus emerges not within science as a whole, but within two opposing camps, each with little interest in communicating with the other.<\/p>\n

The second challenge is when scientists achieve consensus, arriving at a \u201cflat\u201d trajectory, only to find it rendered effectively moot by sociopolitical factors. This is touched on<\/a> by Pinch and Bijker, who, writing about technological development, stress the importance of the broader sociological context in assigning value to a given \u201cartifact.\u201d Even if research produces a device, or a conclusion that is well-constructed and meets what its makers consider to be an urgent societal need, these efforts will amount to little if society is uninterested in what science has to say. There are many examples of this in the historical record, including most saliently in the early challenges around establishing tobacco<\/a> as a cause of lung cancer. Relatedly, perhaps the most pressing current example of this is climate change. Though the reality of climate change is overwhelmingly backed by the scientific consensus, the refusal of certain lawmakers<\/a> and their constituents to accept these data has stymied progress on this issue.<\/p>\n

Moving beyond doubt to knowing and acting<\/h3>\n

Given these challenges, and the ever-present uncertainty<\/a> surrounding all scientific inquiry, it is important for us to recognize that there are times when we do indeed know<\/em> something, and to be able to communicate to the world why we are confident in this knowledge.<\/p>\n

As with many other matters, Socrates foresaw this issue in Plato\u2019s Theaetetus<\/em><\/a>, and suggested that knowledge could be defined as \u201ctrue belief with an account.\u201d I have written before<\/a> about how this \u201caccount\u201d might be interpreted as the scientific method by which we test our theories and arrive, ultimately, at our conclusions. But there is another meaning to \u201caccount,\u201d a word which can also refer to<\/a> \u201ca statement explaining one\u2019s conduct.\u201d For all the uncertainty that can sometimes characterize scientific inquiry, there are also occasions when we do<\/em> know something, and when we also know how<\/em> we know it. In an age when politics and culture exercise a kind of veto power over even our most carefully considered findings, there is value in knowing when we, collectively, are right. Understanding the nuances that get us to scientific consensus may help clarify our thinking to this end. To be able to recognize when scientific consensus points us towards a sound conclusion empowers us to act boldly on behalf of measures that we know will improve the health of populations.
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I hope everyone has a terrific week. Until next week.<\/p>\n

Warm regards,<\/p>\n

Sandro<\/p>\n

Sandro Galea, MD, DrPH
Dean and Robert A. Knox Professor
Boston University School of Public Health
Twitter:\u00a0<\/span>@sandrogalea<\/a><\/p>\n

Acknowledgement: I am grateful to Eric DelGizzo<\/a> for his contributions to this Dean\u2019s Note.<\/em><\/p>\n

Previous Dean\u2019s Notes are archived at: https:\/\/www.bu.edu\/sph\/tag\/deans-note\/<\/a><\/p>","protected":false},"excerpt":{"rendered":"

How scientific consensus is formed, and how it can be mobilized to create healthier populations.<\/p>\n","protected":false},"author":8472,"featured_media":68217,"comment_status":"closed","ping_status":"open","template":"","meta":{"bu_prepress_billboard":"","_bu_prepress_primary_term":"","_bu_prepress_primary_term_manual":""},"tags":[1729,2565,1997],"bu-publication":[3516],"sphnews-article-category":[3519,3527,3531],"sphnews-topic":[],"bu_edition":[],"media_type":[],"profile_tax":[],"_links":{"self":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article\/114819"}],"collection":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article"}],"about":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/types\/bu-article"}],"author":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/users\/8472"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/comments?post=114819"}],"version-history":[{"count":10,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article\/114819\/revisions"}],"predecessor-version":[{"id":191868,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-article\/114819\/revisions\/191868"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/media\/68217"}],"wp:attachment":[{"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/media?parent=114819"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/tags?post=114819"},{"taxonomy":"bu-publication","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu-publication?post=114819"},{"taxonomy":"sphnews-article-category","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/sphnews-article-category?post=114819"},{"taxonomy":"sphnews-topic","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/sphnews-topic?post=114819"},{"taxonomy":"bu_edition","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/bu_edition?post=114819"},{"taxonomy":"media_type","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/media_type?post=114819"},{"taxonomy":"profile_tax","embeddable":true,"href":"https:\/\/www.bu.edu\/sph\/wp-json\/wp\/v2\/profile_tax?post=114819"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}