“Skeptics” believe the darnedest things. One of their favorite mythconceptions is that scientists are under pressure to agree.

Far from it. Science is all about overturning the consensus; there’s no glory in conformity. If the prevailing view never changed then all you’d have is “settled science,” and scientists have a word for that kind of thing: “religion.”

That’s why everyone who works in (say) climate science is driven by one goal: to be the next Michael Mann, the researcher who changed everything we thought we knew about the Medieval Warm Period, the Little Ice Age and the rest of the last 1000 years of climatic change. By proving the then-consensus view wrong, Mann won instant respect and credibility throughout the scientific world.

Having introduced a totally new consensus, Mann has been striving ever since to debunk his own discovery. His inability to do so is a mark of the significance of his work, as well as the maturity of climate science.

So strong is Mann’s belief in the need to overturn received wisdom that he volunteers two evenings a week as a mentor for Paradigm Busters, a program that empowers early-career scientists to say no to consensus. (This week Mann has been teaching his protégés the all-important difference between true consensi and false consensi—a distinction too often lost in facile platitudes about the need to overturn received wisdom.)

Any scientist will tell you the same thing: getting scientists to agree on anything is like herding cats.

Non-scientists often find this simile confusing, so let me explain how cats differ from ungulates. In order to adapt to their climate, the ancestors of modern cats evolved claws. This mutation made it impossible, linguistically speaking, to corral them into a “herd.”

So when we see 97% of cats going in the same direction, we can be highly confident that either:

•   they’re not scientists, or
•   skepticism can no longer be justified by the evidence.

At this point it’s mandatory for “skeptics” to object that consensus is not evidence of anything. Like all skeptic arguments, this is misguided and wrong. While it is true that consensus is not evidence of anything, to imply that this somehow means all the “cats” are engaged in a conspiracy to go in the wrong direction is an absurd strawman, not to mention an example of the anthropomorphic fallacy!

A scientific consensus has very occasionally been wrong in the past, but when you look at the details you find, time and time again, that the prevailing view was based on ignorance of key information. In almost every case, we now know better.

The current consensus in climate science, on the other hand, is based on all the evidence we do have.

But how much do we have, exactly? Well, we’re not climate scientists, so we can’t personally judge the strength of the evidence; all we can do is infer it from the strength of the consensus. Scientists follow the evidence, so the science has to be pretty overwhelming for them to be 97% sure the evidence is right.

When only 3% of known science contradicts the evidence, scientists have a term for that too.

“Settled science.”