So Much Misleading Talk Occurs in Claims of a Scientific Consensus

These days scientists enjoy a reputation for being honest people, and probably most of them are honest. But it is strange that scientists in general enjoy such a reputation for speaking honestly. Very many scientists are guilty of misleading statements. In the post here I describe some of the many misleading speech patterns of many scientists. In this post I will focus on one of the examples I gave in that post: the misleading use of the term "scientific consensus." Nowadays, this term is being used massively by scientists and science journalists, often in a very misleading way. 

The first thing that should be discussed is: what is meant by the term "consensus"? To get a proper sense of the denotation and connotation of that word, we should look at how "consensus" is defined by various dictionaries. Below is how "consensus" is defined by various dictionaries and authorities:

• A Google search for "consensus definition" gives "a general agreement" as the first result.
• The Merriam-Webster dictionary gives us two definitions of "consensus" that disagree with each other. The first definition is "general agreement; unanimity." The second definition is "the judgment arrived at by most of those concerned." The first definition specifies 100%, and the second definition merely means 51% or more. 
• Dictionary.com also gives us two defintions of "consensus" that disagree with each other. The first is "majority of opinion." The second is "general agreement or concord; harmony." The second definition implies near-unanimity; the first does not. 
• The Collins dictionary defines "consensus" as "general agreement among a group of people."
• The Britannica dictionary defines "consensus" as "a general agreement about something : an idea or opinion that is shared by all the people in a group."
• Vocabulary.com defines "consensus" as "agreement in the judgment or opinion reached by a group as a whole," and at the very beginning of the page with this definition, we are told that  "when there's a consensus, everyone agrees on something."
• The Cambridge Dictionary defines "consensus" in two ways: (1) "a generally accepted opinion among a group of people"; (2) "agreement among a group of people."
• The Macmillan dictionary defines "consensus" as "agreement among all the people involved."

From the definitions above, you can make the following conclusions:

(1) "Consensus" is a word that is often defined as if it meant a unanimous opinion on some topic, but also often defined as if it meant a mere majority opinion on some topic.

(2) Because it is often defined as if it meant a unanimous opinion on some topic, "consensus" is undeniably a word with at least a strong connotation of meaning a unanimous opinion on some topic, with everyone agreeing about it.  The connotation of a word is the kind of impression or feeling that the word creates, regardless of how the word is literally defined. 

Because it is defined in ways that conflict with each other, "consensus" is a slippery and ambiguous word to be using. You might call it a very treacherous term, a term very prone to mislead or confuse. Since it has two very different definitions, using the word "consensus" is as potentially misleading as using the word "gay" soon after people first started to use that term to mean "homosexual," at a time when it was hard to tell whether "gay" meant "homosexual" or simply "merry."  

One of many deceptive speech habits occurring in science literature is that misleading claims are being made of a "scientific consensus" about opinions which do not at all involve any unanimity of opinion among scientists. Because of how often "consensus" is defined to mean "unanimty of opinion," such claims are designed to create an impression that scientists agree about something. But typically there is no evidence that anything close to 100% of scientists agree on such an opinion, and in very many cases there is not even good evidence that a strong majority of scientists believe in the opinion. 

Because of the almost total non-existence of secret ballot polls of scientists, there are almost no claims about scientist opinions that are well supported by evidence. We know that certain opinions are what we may call reputed majority opinions of certain types of scientists. For example, it is repeatedly alleged that most cosmologists believe in dark matter and that most biologists believe in the doctrine of common descent, that all species are descended from a common ancestor. But what percentage of cosmologists believe in dark matter, and what percent of biologists believe in the doctrine of common descent? 

You cannot tell such a thing by asking for a show of hands at a meeting of cosmologists or a show of hands at a meeting of biologists. When there is a reputed majority of opinion about something in some scientific field, a scientist in that field may think that he will get in trouble by publicly stating an opinion contrary to the majority in his field.  So such a scientist may fail to honestly state his opinion whenever he can be publicly identified as someone holding a contrarian opinion. 

You can try to figure out what scientists think about a hypothesis by going through their public statements, but that would be a not-very-reliable approach.  Publicly scientists will often make statements that do not show a definite belief about something.  For exampe, having read innumerable scientific papers on memory, I know that an extremely common type of statement in such papers is for a neuroscientist to say something like this: "It is commonly maintained that memories are stored in synapses." But what does that tell us about what the author of the paper believes? You cannot tell. 

The only way to get a reliable measure of the opinion of a scientist is to do a secret ballot poll, one that includes a variety of belief options including "I don't know" or "I'm not sure." However, such polls are virtually never done. When opinion polls of scientists are done, they typically fail to be secret ballots, and also fail to offer a full spectrum of answers including options such as  "I don't know" or "I'm not sure."  

Here are some of the main shady tricks of consensus claimants, people trying to make it sound as if scientists agree about topics when there is no good evidence that such agreement exists:

(1) Inappropriate use of the word "consensus": Given the fact that the word "consensus" is so often defined to mean unanimity of opinion (as we saw by the definitions above), anyone who uses the word "consensus" to describe something that is not a unanimity of opinion should be labeled as someone who has written or spoken in a misleading way. 

(2) Making claims of consensus based on dubious interpretations of scientific papers. The classic example of a misleading analysis of this type was the paper (mentioned below) that analyzed public papers on climate change, and tried to make it sound like the papers showed a 97% consensus on a topic when what was really going on was most of the authors stating no opinion on the topic. 

(3) Using shifting or inconsistent definitions when trying to back up claims of consensus.  A classic trick of consensus claimants is to use shifting, inconsistent language while making consensus claims. For example:

• A Darwinism enthusiast will try to suggest unanimity about evolution by citing some poll suggesting almost all biologists believe that "humans evolve over time." Belief in this very weak claim (disputed by virtually no one) will then be used to make a claim of consensus about an entirely different claim, a much more presumptuous claim, such as a claim of common ancestry of all species or a claim that evolution is the main cause of human origins. 
• To depict unanimity about climate change, someone may cite some poll asking about "whether global warming is real" or about "whether human activities contribute to global warming," and then use those results to claim a consensus that "human activities are the main cause of global warming," which is a proposition more presumptuous than those two claims, or use those results to claim a consensus that "most of global warming is caused by human activities," which is a proposition even more presumptuous than those two claims.   

Consensus claimants often use shady tricks like this

(4) Failing to cite secret ballot polls. A poll of scientists that fails to use a secret ballot technique should not be trusted. If a secret ballot is not used, there will be too large a chance that a scientist will avoid stating a controversial opinion for fear of getting in trouble for defying the reputed norms of his peers. The only reliable way to do an opinion poll of scientists is to do a secret ballot poll, but almost never are such polls done. Unless a poll of scientists specifically claims to have been done using a secret ballot technique, we should always assume no such technique was used. Anyone doubting that scientists would live in fear of getting in trouble by stating unconventional opinions should study my post here, which documents a recent case of a major science journal trying to get a PhD fired because he stated some mildly unconventional opinions in a restrained manner.  

(5) Failing to use polls that offer an "I don't know" or "No Opinion" choice. Opinion polls of scientists that do not offer a choice of "I don't know" or "No opinion" are worthless. So, for example, you do nothing to properly measure scientist opinions on human origins if you offer a choice between "Darwinian natural selection" and "God creating Adam and Eve," and fail to offer a choice such as  "I don't know." 

(6) A misleading use of the phrase "growing consensus," often used for claims not even accepted by a majority of scientists.  One of the many abuses of the word "consensus" occurs when someone makes a claim that there is a "growing consensus" about something, typically referring to some claim that is not even believed by any clear majority. We had an example of this in an article in which a scientist incorrectly claims there is a "growing consensus that spacetime (and thus also matter/energy) is not fundamental but emergent from entangled quantum information." Such an offbeat idea is not held by a majority of scientists or physicists. I may note that every time someone refers to a "growing consensus" they are using the word "consensus" in a way that contradicts one of the definitions of consensus, the definition of agreement or unanimity. If 100% of the people believe in something, such a level of 100% cannot be growing. 

(7) Using subset mining to get a more compelling claim of consensus. Often an attempt to show a unanimity of scientist opinion will fail, with polls showing only something like 80% of scientists agreeing on some topic. Then paper authors will often resort to what we may call subset mining. The goal will be to slice or dice the data until some more compelling claim of consensus can be made. So did your poll of biologists find fewer than 90% of biologists endorsing Darwinian explanation of human origins? Then you can try checking a subset of those biologists: only those calling themselves "evolutionary biologists," and report on how that subset responded. Did your poll of earth scientists find that fewer than 90% of them endorse the claim that global warming is mostly man made? Then you can try checking a subset of such scientists calling themselves "climate scientists," and report on how that subset responded. Do you still have a number not high enough? Then you can get a subset of that subset, reporting on the responses of those who call themselves climate scientists and have also published at least ten papers with "global warming" in their titles.  

One problem with such "subset mining" is that the very terms that scientists use to describe themselves can be an indication of what they believe. So if you select a subset of scientists that calls themselves some particular thing, you may be getting some little clique or faction or tribe that will share some common ideology. Unanimity or near-unanimity in such a small group is not persuasive, and often merely is an indication that a little belief community has formed.  

For example, if rather than polling people calling themselves "biologists" or "ecologists" you poll people who call themselves "evolutionary biologists," it is not too convincing if the great majority endorses conventional Darwinism. Anyone who has decided to call himself an evolutionary biologist is already someone who has declared his allegiance to Darwinist tenets. Similarly, it may be impressive if 90% of physicists were to endorse string theory, but it is not very impressive if 90% of people calling themselves "string theory physicists" endorse string theory. Once a person starts calling himself a string theory physicist, he means he has already endorsed the speculative ideas of string theory. Similarly, it is not necessarily convincing if 97% of people calling themselves "climate scientists" endorse claims that global warming is mostly man made. It could be that the term "climate scientist" is chosen only by those endorsing such claims, with uncertain people calling themselves more general terms such as "earth scientists," "atmospheric scientists," and "meteorologists." 

(8) Bad polling methods relying on voluntary participation. Decades ago I once briefly held two full-time jobs, working for two months as a temporary worker for the US Census Bureau. The US Census Bureau knew the correct way to do a scientific survey. They scientifically selected a certain number of people for polling on one particular topic (how many people use the government's fishing and wildlife services), and then hired workers such as myself to keep calling such people until as many of them as possible answered a series of questions about the topic being researched.  

This produces results much more reliable than a voluntary participation survey (one in which people are mailed a survey form, and may choose to fill out the form or ignore it). There are all kinds of reasons why voluntary participation surveys may produce slanted results. It may be that the people who tend to fill out such voluntary surveys are those who feel most passionately about the topic. But what kind of opinion poll are you getting when you are getting answers from those who feel most passionately about the topic? Possibly some result that does not reflect the opinion of scientists in general. 

Here is a hypothetical example. Let's suppose 90% of scientists don't believe in Theory X, and don't care about it. Then suppose a survey form is mailed to 1000 scientists asking what they think about Theory X. It could be that 90% of the 100 respondents are those who  believe in Theory X, and are interested enough to fill out the survey. The survey might then suggest that 90% of scientists believe in Theory X, even though 90% of them do not believe in it.

The recent paper "Knowledge overconfidence is associated with anti-consensus views on controversial scientific issues" gives us an example of misleading language using the word "consensus." Some of the misleading parts of this paper are listed below:

(1) A groundless claim is made of a scientist consensus that "consuming foods with ingredients derived from GM

crops is no riskier than consuming foods modified by

conventional plant improvement techniques." The only two references given to support this statement are not references to polls of scientists (one of the references being a brash board of directors statement, and the other being a very mixed report that never makes such a claim about genetically modified crops).

(2) We also have the duplicity of switching the definition of evolution, defining it one place as "humans have evolved over time" and defining it another place as "an explanation of human origins."   The claim that evolution adequately explains human origins is a claim vastly more presumptuous than the mere claim that humans have evolved over time. Because gene pools undeniably change over time, almost no one disputes the idea that humans have in some sense evolved over time.

An example of a paper misleadingly using the word "consensus" is the 2021 paper "Consensus revisited: quantifying scientific

agreement on climate change and climate expertise among Earth scientists 10 years later." The study involved a voluntary participation email survey of 10,929 Earth scientists, using a source listing geosciences faculty. 2780 responded, and 7.9% listed "natural processes" as the main cause for global warming, with 91.1% listing "human activity" as the main cause for global warming. The title  misleadingly suggests there is "consensus" and "agreement" among Earth scientists about global warming, but its data does not show that, with about 8% of the respondents giving a response defying such an alleged consensus.

Another example of a paper misleadingly using the word "consensus" is the 2013 paper "Quantifying the consensus on anthropogenic global warming in the scientific literature."  The paper led to widespread claims that 97% of climate scientists agree that global warming is mostly caused by humans, but it did not find any such thing. Instead, after examining the literature for "11 944 climate abstracts from 1991–2011 matching the topics 'global climate change' or 'global warming' " the study found that 

"66.4% of abstracts expressed no position" on whether global warming was mostly caused by humans, and that of the abstracts that did state a position on this topic, 97.1 endorsed the position that global warming is mostly caused by humans. There is a very large difference between such a finding and a finding that 97% of climate scientists claim that global warming is mostly caused by humans. 

Oddly, there are scientific consensus claims that are utterly inconsistent with statements that are widely made these days by scientists. It has become increasingly common and mainstream for scientists to list a "problem of consciousness" as an unsolved problem. But if we don't know what causes consciousness, then (1) we have no basis for confidence in claims that the brain is the cause of the human mind, and (2) we have no basis for claiming that we understand the origin of the human race. If you don't understand the origin of consciousness, then you have no business claiming that you understand the origin of humans. In this case two of the claimed "consensus opinions" of scientists (the claim that evolution explains human origins and the claim that brains produce minds) turn out to be inconsistent with another claim that scientists are widely making these days (that we do not understand how humans are conscious). 

There have been so many outrageous misstatements by scientists and science writers that used the word "consensus" that I must recommend the general principle that as a rule of thumb you should tend to be suspicious whenever you hear a scientist or science writer making any claim about what scientists believe that uses the word "consensus." The whole idea of appealing to an alleged consensus is a poor one. When people have facts to back up their claims, they cite facts. When they lack adequate facts to back up their claims, they may appeal to some alleged consensus of experts. When we hear appeals to some alleged consensus of scientists, it does not show the claim  is poorly established, but it may be a reason for suspecting such a thing. Nobody ever says there is a consensus of scientists that Jupiter exists. Someone wanting to show that Jupiter exists will show a space probe photo of Jupiter or a telescope photo of Jupiter. 

I was pleased to see that the US Congress recently took action that will reduce US greenhouse gases, and I have lived a very "low carbon" lifestyle for the past ten years (although who knows whether that is being "global warming attentive" or just being a garden-variety cheapskate). Scientists reasonably wishing to provoke public action relating to global warming should appeal to the simple facts that support the probably correct claim that humans are the main cause of global warming, instead of making shaky claims misleadingly suggesting that there is unanimity of opinion among experts on this topic. Knowing that academia tribes are subject to groupthink effects, people are not very persuaded by claims of agreement in some specialized tribe of scientists that may be following a "follow the herd" rule.  Rather than appealing to some agreement in such a tribe, it is better to appeal to facts.  

For reasons given above, you should be extremely suspicious about all claims that there is a scientific consensus that the brain produces the mind, or a consensus that memories are stored in brains. There is no good evidence that all scientists or almost all scientists hold such beliefs. There seems to exist no study doing a secret ballot of the opinions of biologists about such topics.    

If you do a Google search using the phrase "poll of neuroscientists" you will find almost no examples of polls of neuroscientists other than a 2002 study entitled "Do You Know Your Brain? A Survey on Public Neuroscience Literacy at the Closing of the Decade of the Brain." The study did a poll of neuroscientists around the globe, but no claim is made that any attempt at a secret ballot was made. So we should therefore assume that the poll was not a secret ballot. In any poll that was not a secret ballot, scientists may have tended to answer in some way matching perceived conventions, to avoid getting in trouble by stating some opinion contrary to the supposed majority opinion in their field. 

The study's statement about the polling of neuroscientist has an inconsistent sound to it. We read this:

"As a reference against which to compare the public’s responses, 270 regular members of the Society for Neuroscience were consulted via e-mail, with an electronic, English version of the same questionnaire. A total of 2193 filled-in questionnaires were collected, 35 of which were from senior neuroscientists of different nationalities."

But how could 2193 questionnaires be returned, when only 270 were polled? The numbers given here don't sound right. 

The poll gives some evidence that many neuroscientists do not hold the opinions commonly attributed to them. Asked whether they agree with the claim that "memory is stored in the brain much like in a computer, that is, each remembrance goes in a tiny piece of the brain," 82% answered "No," 12% answered "Don't know," and only 6% answered "Yes."  9% answered "Don't know" when asked whether they agree "the mind is a product of the working of the brain." When asked whether they agree with the statement "memory is stored in a net of many cells scattered throughout the brain," 77% said "Yes," 9% said "No," and 14% said "Don't know." When asked whether "'State of mind' is a reflection of the brain state in a given moment," 77% said "Yes," 3% said "No," and 20% said "Don't know." When asked whether they agree with the claim "Without a brain, consciousness is not possible,"  83% answered "Yes," 6% answered "No," and 11% answered "Don't know."  When asked whether they agreed with the claim "the mind is the result of the action of the spirit, or of the soul, on the brain," 35% answered "Don't know."

Although very limited as evidence for what neuroscientists are  thinking (with answers from only 35 senior neuroscientists), this poll is sufficient to show that the beliefs conventionally attributed to neuroscientists are not held by all or almost all neuroscientists.  In general, we lack reliable data on what neuroscientists believe. There seem to be no studies that perform (using scientific polling practices) a secret ballot of neuroscientists asking how much they agree with the beliefs commonly attributed to neuroscientists. So people should not be talking about a "consensus of neuroscientists" regarding the cause of mind or the storage place of memory, particularly since the term "consensus" suggests a unanimity that does not exist.

Let us consider a very interesting type of alleged consensus that I may call a "leader's new clothes" consensus.  Let us imagine a small company of about 20 employees that has a weekly employee meeting every Monday morning. On one Monday morning after all the employees have gathered in a conference room for the meeting, the company's leader comes in wearing flashy new clothes that are both very ugly and ridiculous-looking. Immediately the leader says, "I just paid $900 for this new outfit -- raise your hand if you think I look great in these clothes."   

Now if it is known that the leader is someone who can get angry and fire people for slight offenses, it is quite possible that all twenty of the employees might raise their hand in such a situation, even though not one single one of them believes that the leader looks good in his ugly new clothes.  In such a case the "public consensus" is 100% different from the private consensus. A secret ballot would have revealed the discrepancy. 

The point of this example is that appeals to some alleged public consensus are notoriously unreliable. So arguing from some alleged consensus of some group is a weak and unreliable form of reasoning.  The only way to get a reliable measure of the opinion of people on something is to do a secret ballot, and there virtually never occurs secret ballots of scientists asking about their opinions on scientific matters. We have no idea of whether the private beliefs of scientists differ very much from the public facade they present.  For example, we have no idea whether it is actually true that almost all  scientists think your mind is merely the product of your brain. It could easily be that 35% of them doubt such a doctrine, but speak differently in public for the sake of "fitting in," avoiding "heresy trouble" and seeming to conform to the perceived norms of their social group. 

Two very simple rules scientists should follow are (1) don't claim you understand something that you don't understand; (2) don't claim or insinuate that scientists all agree on something when you lack any good evidence that such agreement exists. Nature is very, very complex, and gives up its secrets very, very slowly, often eventually making knowledge boasts of scientists look ridiculous. 

For more on this topic, see my post here, entitled "Exaggerations Abound When People Talk About a Scientific Consensus."