UQx DENIAL101x Knowledge Based Consensus

In a debate, just having a bunch of people
agree isn’t enough. Groups of people agree, and turn out to be wrong, all the time. What makes scientific consensus different?
Scientific consensus is different because it relies on three important ingredients.
Evidence. Everyone involved agreeing upon standards for that evidence. And agreement
from many different groups from many different backgrounds. In the study of the philosophy of science,
we would say that consensus is likely to be correct when it is knowledge-based. And consensus
is knowledge-based when it meets three important conditions: Consilience of Evidence, Social
Calibration, and Social Diversity. Consilience basically means having many lines
of evidence that are independent from, but in agreement with one another, that all point
to the same conclusion. You can think of it like this: A friend is cleaning out his old games, and
gives you a bunch of puzzle pieces. He was cleaning in a hurry, and just threw pieces
in an old shoebox. You don’t know what the puzzle will look like, or even if the pieces
are really all from the same puzzle. Maybe the pieces all look like they’re showing
something similar, but don’t actually fit together. Or maybe the puzzle pieces sort of fit together,
but look like they would have to come from very different pictures. When pieces of the puzzle fit together and
show a picture that makes sense, you can be confident that you’re on the right track. Science depends on evidence coming together
and telling the same story. When we look at the average temperature of the earth, we can
see a bunch of different lines of evidence pointing to the same conclusion. Thermometers on the ground, on ships in the
ocean, and on balloons in the air all show an increase in temperature. Glaciers around
the world are melting. Sea level is rising. Moisture in the air is increasing. All of
these things tell us the world is getting hotter. The puzzle pieces fit together and the picture
is clear. Evidence is a big part of what makes science
successful. And that means we have to make sure we’re all using the same standards
of evidence and speaking the same language, figuratively at least. We call this Social
Calibration. It may sound obvious, but people need to be
in agreement about the concepts they’re discussing before they can come to a meaningful
conclusion. To be able to address the question of whether
the planet is warming, you have to agree on some basic concepts. It might sound silly
to you and me, but there are climate contrarians who actually deny that there even is such a thing as
a global temperature, as a concept! But of course we can take temperature measurements
from across the planet to get an average of the whole global temperature. People need to agree on what counts as a valid
way of answering a question as well. Someone might feel that the answer was revealed
to him in a dream. Someone else might have claimed to have found an answer in an ancient prophecy. But when dealing with scientific questions, it’s
important that we’re relying on the rigorous standards of scientific inquiry. Consilience of Evidence and Social Calibration are important but still might not be enough. To be really confident that consensus is correct, it also helps to
see agreement coming from many different groups from many different backgrounds. In other
words, we want to see Social Diversity. To understand why, it helps to look at cases
in which a lack of Social Diversity can lead to the wrong conclusions. One is plain old bad luck. It is always possible
to reach a conclusion of “yes” when the answer correctly is really “no” or vice versa.
It could be a statistical fluke. Or contaminated materials. Or even something dependant on
the location of the group performing the experiment. Having many different groups from many different
backgrounds can do a lot to rule out such problems. Another way in which a lack of diversity can
lead to agreement that turns out to be wrong is groupthink. There is a tendency for groups of small numbers
or highly similar groups to attempt to minimize disagreement and promote conformity. A desire
for harmony within the group can cause people to ignore reservations they may have, and
reach agreement for the sake of agreeing, rather than based on standards of evidence. A large, diverse group will have less of an
inclination towards groupthink, as differences among the group exist from the outset. Cultural bias is another way in which a lack
of diversity can lead to incorrect conclusions. Scientists are products of their cultures,
and different cultures have different preferences for how the world should be. Including scientific
viewpoints from as many different cultures as possible helps ensure that agreement isn’t
the product of values rather than evidence. Over 80 national science academies around
the world agree that humans are causing global warming. None disagree. Having a socially diverse consensus also guards
against self-deception and outright fraud. Those with no stake in an outcome, or who
stand to lose rather than gain from an outcome, reaching the same conclusion as those who
might benefit from it increases our confidence that the conclusion is correct. The consensus on climate shows clear Social
Diversity. Keeping these conditions in mind, we can look
at examples from the past when consensus supposedly has been wrong. Climate contrarians are fond of holding up
such examples as reasons to doubt the current consensus on climate is correct. A frequent example is
that there was a consensus in the scientific community against continental movement, which
plate tectonics later proved to be wrong. But is this an example of a Knowledge-Based
Consensus that failed? Does this example meet the conditions of Consilience of Evidence,
Social Calibration, and Social Diversity? Let’s assume that we’re talking only about
physical scientists actively engaged in the issue. For the sake of argument, we’ll say
that the condition of Social Calibration was met. There was no consilience of evidence against
continental drift. Some evidence that landmasses moved was known for hundreds of years. But
the evidence didn’t point conclusively towards a coherent picture for movement. Perhaps more interesting was how disagreement
on this issue was related to nationality. Scientists, with basically the same training,
looking at the same evidence, were coming to different conclusions based on where they
lived. Science historian Naomi Oreskes has shown
how the cultural ideals among geologists in North America differed from those from Europe,
and how that affected their scientific views. Scientists in America tended to value democracy
and were hostile to authoritarian decrees. They favored bottom up, inductive methods
of interpreting the evidence. They were leery of top-down, Big Man, Big Theory explanations.
And so they were resistant to the evidence for a continental drift in a way that their peers
in Europe, or South Africa and Australia, weren’t. The opposition to continental drift was not
a consensus. And definitely not a knowledge-based one. Other examples used to cast doubt on
the modern consensus on climate fare the same. When the pieces of the puzzle fit together, you have a Consilience of Evidence. When everyone is using the same
standards of evidence and speaking the same language, you have Social Calibration. When
agreement is widespread across many different groups of people from many different backgrounds,
you have Social Diversity. When you have all three, you have a Knowledge-Based
Consensus. And you can be confident that it’s correct.

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