Cognition & Reality

Thursday, 6 January 2011

Scientific Consensus

Filed under: Uncategorized — drtone @ 3:20 pm

I hate when this happens. I start thinking about a controversy, and then all my previous concerns about it come to the fore. That’s what occurred yesterday in connection with my entry on AIDS. Especially because of a comment I received, but also as a natural consequence of revisiting a subject in which I was previously interested, memories of my frustration and irritation regarding the topic flowed back. Today’s entry reflects that process.

Even a cursory reading of some of what is out there on AIDS will lead to the phrase “scientific consensus.” For example, Thabo Mbeki’s notorious rejection of the “scientific consensus” regarding the causal link between aquired immune deficiency syndrome (AIDS) and the human immunodeficiency virus (HIV) has forever stamped him as a bad man, despite his enormous contributions to life in South Africa. “Scientific consensus” is also a term of prominence in discussions of climate change and global warming. It is employed in these contexts as the last word in any debate, and  those who question the “scientific consensus” are frequently labeled as “deniers” or even “denialists.” Rarely, if ever, does anyone ask some simple questions: What is a “scientific consensus”? How does a “scientific consensus” arise? How would it function? I do not mean to address all of these questions in detail, but merely to point out, first of all, that it is legitimate to ask them, and also to suggest that there is hardly a one-to-one relationship between “scientific consensus” and the truth.

In The Structure of Scientific Revolutions, Thomas Kuhn showed that scientific knowledge does not proceed along a smooth curve, nor is it based simply on the accumulation of data. On the contrary, science is a social phenomenon that tends to organize around what Kuhn called “paradigms,” and science is an activity that can be described in sociological terms. Scientific understanding of the cosmos was once organized around a paradigm, attributed to Ptolemy, placing the earth at the center of a set of “orbs.” Eventually, that geocentric paradigm, “scientific consensus,” was replaced, through a series of conjectural steps, Kuhn argued, rather than through more accurate observations, by the heliocentric paradigm associated with Copernicus, which gave way to one that places the earth in a cosmos that has no center, the “scientific consensus” regarding the universe we accept today (with many amendments).

The point I am making here, with reference to Kuhn, is that it is dangerous to give a “scientific consensus” some kind of special status, although it almost always acquires such a status, people being what they are. The Ptolemaic conception, as the model of the universe accepted by the Church, was literally sacrosanct. Galileo and others were severely punished for questioning it. To us, a geocentric conception of the cosmos seems silly, but a few hundred years ago rejecting it could be a matter of life and death. Mbeki is not the first person to be destroyed for questioning the “scientific consensus.” (The self-serving blame AIDS activists heap on Mbeki for hundreds of thousands of deaths, based solely on conjecture but forever a part of the man’s biography, could be a case in point for anyone who wishes to know what chutzpah means.)

Those of us who went to school in the fifties remember being taught that the apparent fit of the coasts of South America and Africa was an amusing coincidence. Alfred Wegener, the chief proponent of “continental drift,” the central feature of plate tectonics theory, could not buy an audience for his theory that the continents look like they fit together basically because they do fit together. His views were regularly attacked by geologists, most prominently by the great paleontologist George Gaylord Simpson, one of the most respected and revered men in the history of science. Today, Wegener’s views are the foundation of the “scientific consensus” in geology.

Thus, the “scientific consensus” can be dead wrong, sometimes with a moral attached. Practically since the beginning of the serious study of neurophysiology, it was axiomatic, the “scientific consensus,” that brain cells do not regenerate. The idea that they do regenerate was considered laughable. Now they do. The “Big Bang theory” was once derisively dismissed by astrophysicists, who then almost universally accepted a “steady-state” theory of the universe. Now the Big Bang rules the roost. In the nineteenth century, the “scientific consensus” was that mental disorders were inherited. In the twentieth century, under the influence of Freud, that view was overthrown. In the the twenty-first century, the “scientific consensus” has returned to the view held in the nineteenth, a topic on which I have commented several times, including here.

Until recently, less than 100 years ago, it was the “scientific consensus” that the “White Race” was superior to the other “races” of humans, a concept used to justify not only Nazism, but also slavery, segregation, and colonialism. Everyone believed it, including those who would count as political progressives by today’s reckoning. Not only do we now find such ideas disgusting, but the supposition that humans can be divided into “races” has undergone many changes, and it is now the “scientific consensus” that the concept of race is, at best, deeply flawed.

A “scientific consensus” can be useful in practical terms, because it guides research, but it can also stand in the way of progress, and can, at its worst, be used to support views of questionable moral content, Social Darwinism, for example. This may seem obvious, a commonplace hardly worth mentioning, except that the purportedly relevant “scientific consensus” is regularly employed by both AIDS activists and “global warming” activists to bludgeon critics. As I have demonstrated here, it is at best a treacherous form of argument. By its very nature, the “scientific consensus” has a way of changing. What was absolutely true yesterday can become little more than a joke today.



  1. Hey! This was excellent late night reading. I’ve never held any truck with “scientific concensus.” It was great to have someone point out its flaws and put them out there to examine them pants down looking straight on. I loved how many examples you put forward. This was well written and very entertaning.

    Comment by annie wallack — Saturday, 8 January 2011 @ 6:23 am | Reply

  2. […] A few daze ago, I mentioned the former “scientific consensus” around the relative development of the so-called human “races,” placing members of the “White” race on top. At the time this belief was forming and being promulgated, the latter half of the nineteenth century, White men had more or less finished conquering the world, and were naturally looking for justification they needed for the various crimes they had committed in doing so. […]

    Pingback by Louis Aggasiz & The White Man’s Burden « Cognition & Reality — Wednesday, 12 January 2011 @ 2:58 pm | Reply

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