Scientific Consensus Trick
Person 1: This scientist says (some crazy thing). . .
Person 2: But that is not what the consensus is in that field.
Person 1: Science is not a popularity contest. If science works by simply voting for the most popular choice, that would be a band-wagon fallacy. Scientific consensus of a field is a complete fallacy.
This argument is promoted by apologists as a trick to undermine the authority of the scientific consensus. Sometimes they will point out that there was a time when most scientists thought the earth was the middle of the universe. That is true, science has learned over time and replaced old theories with new ones, but the scientific consensus remains the most trusted source of knowledge of the world.
The collective opinion of a group of experts is valid if the topic is one they are experts in. This is the best opinion available.
The bandwagon fallacy is believing in the collective opinion of people who are not experts in the topic at question.
A Rogue Expert
The apologist would like you to believe that a hand picked expert is right, when all the rest of the scientific field is wrong.
People exist with all manner of credentials with opinions that are the opposite of the current scientific consensus. These citations are dug up to counter a particular claim that might be based on a widely held scientific consensus. There are individuals with a PhD in biology who claim that creationism is the real and true origin of all life on the planet. There are people with a degree in climatology who claim that the earth is actually cooling. These people are crack-pots, and they get their support by speaking as an authority on topic that non-scientific people want to hear.
We you respond that many or most scientists in that field disagree, and that no institution in that field supports that position, they respond: "science is not a popularity contest" and "the majority opinion is a bandwagon fallacy."
Bandwagon Fallacy
The apologist would like you to believe scientific consensus is a bandwagon fallacy.
The bandwagon fallacy is when you ask the general public who are not experts, and who might have frivolous answers, about a topic that they have no particular expertise in. The opinion of the general public should on the average be no better than an average person on the street. Worse, people are persuaded regularly by fads or ideas that are in fashion. This is to say they jump on the bandwagon just because everyone else is doing it.
We should be worried about arguing that something is true just because everyone around us is saying it. The fallacy is that the crowd around us is not an expert in the topic, so that fact that a majority says one thing is not a reliable source. If everyone around us is saying the peanut butter is healthier than a banana, we should take it with a grain of salt because everyone around us is not an expert on nutrition. Instead, we should get the opinion of an expert.
But scientific consensus is not a bandwagon. It is instead the opinion of a collection of experts in a particular field. Because the people being polled are experts, their collective opinion is the absolute best opinion we can get.
Expertise
The apologist would like you to believe there are no experts.
A scientist who has been working exclusively in a field for 20 to 30 years, and an environment where they will be allowed to say something only if it is backed by careful research and evidence. Reputation is everything in science, and to maintain that, the scientist needs to be diligent and accurate in everything that is done. When you spend that amount of time on a topic, you naturally get to know quite a bit about what is and is not in the realm of possible. They are real experts in the field.
The apologist does not want their audience to believe that anyone is particularly expert in anything at all, because that allows their crack-pot ideas to appear more reasonable. Persuasive leaders will always work to undermine the credibility of the experts that exist who oppose their positions. This way, they can bring in their radical opinions, and allow them to stand head-to-head with opinions of experts.
Scientific Consensus Changes
The apologist would like you to believe scientific consensus is regularly wrong.
Yes it is true that scientific consensus does change over time as we learn new things. In 1850 people thought objects could travel at any speed. By 1950 the consensus was that the speed of light is fastest anything can go. But Newtonian mechanics was never found to be wrong at normal speeds: the different is only seen at very high velocities. All of the experiments that Newton and subsequent physicists did are still just as true and accurate as they ever were because they were based on evidence. That evidence was not eliminated by Einstein.
It takes a few decades for the consensus on any give topic to settle down. During the first years opinions may vary widely. But once it settles to the point that 90% of the scientists in the field agree, that is always found to be true in the future. Any field with that level of consensus within the field can't be very far from the truth.
Science Should be Challenged
The apologist would like you to believe science is accepted on faith without question.
Of course this is true: everyone should be skeptical of any claim, nobody is more rigorously skeptical than the method of science done today. The point of a peer reivew is to ask all those questions, and to reject anything that has no solid foundation. To check that all the right procedures were done, and that all the right data is there. It is not perfect, but science has been responsible for every advancement in any field that we have today.
That rigorous challenge is built into science as a way of weeding out the false information. No religion in the world does anything like this.
Having people who no nothing of a topic is not a challenge in any way. Non-experts often lack a basic enough understanding of the topic to even find the questions that should be asked. Apologist often challenge evolution on the basis of "it juts doesn't seem possible." What seems possible to the average person is a bandwagon fallacy, because the average person is not an expert.
If you are an expert actively working in any particular field, then of course you’re up-to-date on all of the various theories, some of which are amply supported by evidence, and some of which are new and you would trust. For example, quantum mechanics there’s the multi-world interpretation, which is accepted by a large number a physicist, but far less than half of them.
If you’re not an expert in the field, then you should stay away from the new theories that are still being sorted out, but instead should stick to the things that are broadly accepted. For example, in quantum mechanics, the Schrödinger equation is accepted by 99% or more of all physicist.
Summary
We all do cherry picking to some extent. We search for someone who backs up our confirmation bias. When we do this we must always be careful that that “expert” is not an outlier, crackpot, or a humbug.
The only way to assure that the person you’re quoting is not a rogue commentator to ask the question: what does that field of science in general believe, for example, scientist, always propose innovative, new theories. Most of them get disproven and sometimes it takes 15 or 20 years to do that. Science works, you need people to try out things, to run an experiment, and propose a theory that explains it. It may then take many years of work to either approve or disprove that theory.
It’s strange how the Christian apologists don’t seem to understand this idea of expertise. When you talk about a generally accepted theory, they will attempt to discredit it by claiming it is a bandwagon fallacy. I’ve even heard people say science doesn’t work by consensus. Right it doesn’t, however, in Facebook discussions, there is no better opinion than the consensus of the experts. Otherwise you ’re simply quoting crackpots.
In reality, science works by being very very skeptical of what anyone claims. The process is to try and tear down every claim, but you can't tear down something with evidence. The evidence speaks louder than the strongest claims. That is why, when you have a field of study, the very best possible opinion you can get, is the consensus of the scientists in that field.
Questions
Q: Is there ever such a thing as scientific consensus? Get two scientists together they always disagree.
Joking aside, scientists are always debating the details on leading edge theories, that is how science works, and the one with the most actual evidence in the end will win the debate. Science is not resolved in every area, and the details of the truth often takes many people to work out.
There are a great many scientific results that are generally accepted and not debated. The Earth goes around the Sun is never debated. Atoms are made of a collection of protons, neutrons, and electrons is never debated. A vast body of knowledge is agreed and accepted. Then, on the leading edge of what is known, there is rather vigorous debate: e.g. is String Theory real?
Q: Scientific consensus is whatever the few guys who control all the research and grant money say it is.
This is the conspiracy theory that science in somehow "owned" by some organization with a motive. For example, the oil industry is rich and known to hire scientists to make particular desired claims.
But nobody owns all the scientists in the world. If for instance the NSF decided to fund only papers supporting a theory "A", even though evidence points to theory "B". What we would find is American papers publishing results saying "A", while papers from Europe, China, and the rest of the world say "B". The NSF is not dominant enough to control the entire scientific field. More important is that following research trying to build on "A" will fail, while research built on "B" succeeds. There is absolutely no way that any conspiracy could control all scientists in a field.
Even the oil industry -- the richest industry in history -- can not control all the climate scientists. Even Christians -- the most powerful religion in history -- can not control all of the biology papers.
The grand conspiracy theory that science is controlled by a secret cabal of liberal politicians just does not stand up to casual investigation. Furthermore, in such a grand conspiracy we certainly would fine some letters, memos, emails, or some other evidence asking people to falsify results if performed on such a grand scale. It is just not credible.