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Skepticism and Pseudoskepticism in the
Climate Change Wars
Doug Campbell
Department of Philosophy
University of Canterbury
What is skepticism?
• First pass: a skeptic is
someone who
opposes bullshit.
• Okay: but what’s
‘bullshit?’
• How is this technical
term to be unpacked?
What do we mean by ‘bullshit’?
•
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
A very incomplete list:
Astrology
Conspiracy theories
Dowsing
Ghosts
Crop circles
UFOs
Alien abduction
Religious miracles
Religion itself (??)
Homeopathy and other forms of medical quackery
Telepathy
Precognition
Telekinesis
The Loch Ness monster, Big Foot, and other cryptids.
But how are to decide what goes on
the list, in controversial cases?
• Type I error.
– We put something on the ‘bullshit list’ that doesn’t belong
there.
– We are ‘too skeptical’.
– E.g., we have fallen prey to vested interests who want to
discredit a theory that is in fact scientifically credible.
• Type II error.
– We exclude something from the ‘bullshit list’ that does
belong there.
– We are not skeptical enough.
– E.g., we have fallen prey to vested interests who stand to
gain from a scientifically implausible claim being accepted.
The climate change case
• Mainstream view
– “Business as usual” anthropogenic emissions of
greenhouse gasses will cause costly and dangerous
dangerous climate change over a decadal timescale.
• Contrarian view.
– Denies the above, and holds that the mainstream
view belongs on the skeptic’s “bullshit list”.
– Holds that climate change science has been captured
by environmentalists and other vested interests.
The contrarian view
(as presented in ‘The Skeptics Handbook”)
We paid to fin a “cri si s”
The Question
• Which is right – the mainstream view, or the
contrarian view?
• Does the mainstream view belong on a
skeptic’s “bullshit list”, or not?
How I came to be interested in this
Denis Dutton
1944-2010
Co-founder and first
chair of the NZ
Skeptics
Climate Debate Daily
• The dispiriting truth
– Both sides read only their own side.
– Confirmation bias is rampant.
– Neither Denis nor I shifted our views one iota.
• My theory: Denis suffered from confirmation
bias.
• Denis’s theory: Doug suffers from confirmation
bias.
• So what objective basis can I have for thinking I
am right?
Plan
• Three approaches that don’t work very well
1. Find the answer by applying the principles of
skepticism.
2. Find the answer by learning a lot of climate
science
3. Find the answer by trusting climate science
• My suggestion
– Apply bogus argument test
Approach 1: apply the methods of
skepticsim
• The skeptic:
–
–
–
–
Proportions her belief to the evidence
Uses logic
Is careful to avoid fallacious reasoning
Is aware of cognitive biases, including confirmation
bias, and does her utmost not to succumb to them
– Subjects her own preconceived opinions to careful
critical scrutiny
– Listens carefully to the arguments of others
– Gladly renounces her own beliefs if she discovers
strong arguments or evidence against them
The problem
• Supporters of the mainstream view claim that
they are properly applying skeptical methods, but
that the contrarians are misapplying them.
• However, the contrarians make precisely the
opposite claim.
• So this approach devolves into a shouting match
about who is being a ‘proper’ skeptic.
Approach 2: find the answer by
learning a lot of climate change
science
• Under this approach, you find out which side
is right by oneself becoming an expert in
climate change science.
• Having gained this expertise, one will then be
in a position to make an authoritative
judgment about whether mainstream AGW
science is credible, or not.
The problem
• This approach works well if one has both the
time and the ability to learn the science.
• But:
1. Most of us don’t.
2. The science of climate change is enormously
broad, involving everything from deep ocean
currents to permafrost to clouds to airborne
dust. No one can understand all aspects of it.
Approach 3: Find the answer by
trusting climate science
• The great majority of scientists support the
mainstream view.
• The world’s most prestigious scientific
academies have come out in support of
climate change science (e.g., the US’s National
Academy of Science, the UK’s Royal Academy,
and 32 other national academies of science).
The problem
• To repudiate the contrarian view on the basis
that the great majority of scientists disagree
with it is to beg the question against the
contrarians.
• The contrarians frankly acknowledge that
what they are saying goes against mainstream
climate science.
• But they claim that mainstream climate
science is bad science.
Sometimes science goes wrong
• Ben Goldacre has made a strong case for thinking that a
great deal of dodgey science has been used by the
pharmaceutical industry to get dugs on the market.
Problems in the science of psychology
• Reported in August 2015: an international
team of experts repeated 100 experiments
published in top psychology journals and
found that they could reproduce only 36% of
original findings.
• 75% of social psychology experiments and half
of cognitive studies failed the replication test
• If the climate change contrarians are right, then
the science of climate change is a bit like the
science done by pharmaceutical companies, or
experimental social psychology. Its results cannot
be trusted.
• Can we simply dismiss this claim outright? No.
• But it does put a big burden of proof on the
climate change contrarians.
– If you are going to claim that the world’s most
prestigious scientific academies are all making a
horrible mistake, then you had better have a good
argument.
– “Extraordinary claims require extraordinary evidence”.
The Bogus Argument Test
• Suppose someone makes an extraordinary claim,
X.
• They support X with Arguments A, B, C, D and E.
• A cursory examination of Arguments B and E
reveals that they are terrible arguments.
• Then you can pretty safely dismiss X.
• What about Arguments A, C and D? If they have
any good arguments up their sleeve, it is their job
to sort them out from other bad arguments.
The bogus argument test as applied to
Climate Change Contrarianism
2
• The saturation argument
• The CO2 lag argument
Ice cores reveal that CO 2 levels rise and fall hundreds of years
after temperatures change
On average CO 2 rises and falls hundreds of years after temperature does.