I keep saying, from time to time, that I am a sceptic, not just about the imagined catastrophe awaiting us through anthropogenic global warming, or ‘climate change’, but about other statements and about theories in general. In terms of daily life, of course, I ‘take for granted’ all sorts of things that others might be sceptical about. I have found no need yet to be sceptical about them, or I don’t think it matters. I don’t, for example, care much one way or the other about fats of various kinds. I’ll eat butter or margarine, without worrying about the consequences.

What is it to be sceptical about something? My own meaning is that where I am not sure about something I think is important, and can’t reasonably be sure, I am sceptical about claims. That doesn’t mean I think it’s wrong, whatever it is; it is simply that I am not in a position to make a proper judgment. Some other person or organisation may be sure, but that is no real help to me. I need to make up my own mind about it, and for the moment I can’t. Therefore I don’t accept the proposition, at least for the moment. Quine would call it the state of ‘suspended judgment’, one of non-belief rather than of disbelief.

I came across a neat little series of thoughts on the issue of scepticism on the Fabius Maximus website, and that prompted this essay. Much of it comes from a man whose name I didn’t know, but who is credited with the immortal line: ‘extraordinary claims require extraordinary proof’, though there are earlier versions of it from Laplace and David Hume. His name is Marcello Truzzi, and he was once a Professor of Sociology at Eastern Michigan University, where I was once offered a senior job. I was tempted, as an Australian might especially be, at thought of working at EMU, but I went elsewhere. Truzzi was famous for being prepared to investigate the ‘paranormal’, and the claims of protosciences (most of the natural sciences before the mid 19th century) and of pseudosciences (alchemy, for example).

He summed up his position like this:

In science, the burden of proof falls upon the claimant; and the more extraordinary a claim, the heavier is the burden of proof demanded. The true skeptic takes an agnostic position, one that says the claim is not proved rather than disproved. He asserts that the claimant has not borne the burden of proof and that science must continue to build its cognitive map of reality without incorporating the extraordinary claim as a new “fact”. Since the true skeptic does not assert a claim, he has no burden to prove anything. He just goes on using the established theories of “conventional science” as usual. But if a critic asserts that there is evidence for disproof, that he has a negative hypothesis … he is making a claim and therefore also has to bear a burden of proof. (Marcello Truzzi, ‘On Pseudo-Skepticism’, Zetetic Scholar, 12/13, pp3-4, 1987)

Now I like that way of setting things out. I think it is where I am, and where I have been, too. It helps me with the argument with Stephen Mosher that was the subject of a recent essay. I entered this debating arena ten or more years ago by saying that I was an ‘agnostic’, and that I was prepared to accept what I now call the ‘orthodox’ AGW or ‘climate change’ proposition if the argument and data were good enough. As time has passed the data and argument look weaker rather than stronger, but I am still open to persuasion.

Someone else (James H. Hyslop) has called scepticism ‘critical ignorance’, and I like that too: Hyslop adds Open-mindedness is the only scepticism that can claim immunity from prejudice. (The link is in the Truzzi article.) Here is Truzzi again.

Evidence is, then, a matter of degree, and not having enough results in a claimant’s not satisfying the burden of proof. It does not mean disconfirmation of the claim. The proof is insubstantial, and the claim is unaccepted rather than refuted. The claimant is, in effect, told either to give up or go back to find stronger evidence and arguments for a possible later day in the court of science. As a practical matter, an unproved fact is a non-fact.

There is a lot of Popper and Khun in all this, which Truzzi concedes, but the Truzzi essay is well worth reading by those who think of themselves as ‘sceptics’, because he brings all of the various insights into a clear and sensible summary.

Let me deal with one of the familiar red herrings in the scepticism business, about which I have written in the past. You are diagnosed with cancer. Are you sceptical when you hear what the specialist(s) say(s)? Now I have been diagnosed with cancer, and treated for it, and that was 24 years ago, and I am still here. I wasn’t at all sceptical on that occasion. I knew something about the condition, and I knew also that the science was by no means fully developed (we are still searching for a ‘cure for cancer’). Therefore at best there were probabilities, and there were risks.

In the case of ‘climate science’, which I would term a ‘protoscience’ rather than a ‘pseudoscience’, the science is not at all well developed, much less so than in the medical science to do with cancer. I am sceptical of the claims that carbon dioxide is the control knob of our climate, that increasing carbon dioxide in the atmosphere is bound to be bad for us over a human lifetime or two, and that carbon taxes and emissions trading schemes can do anything of any consequence about climate.

Here there is abundant data and argument, and from my perspective, and I think from that of any educated and informed person, those data and the general argument do not powerfully support the AGW orthodoxy. That could change, and I once wrote a piece about what would be necessary for me to change my perspective (and cannot find it). There would need, for example, to be unequivocal evidence that ‘climate sensitivity’ was at the very high end of the IPCC’s range — 4.5, perhaps. But it increasingly looks as though climate sensitivity has a value of around 1, or a little higher. If that is the case, then we do not have a problem with global temperature in the foreseeable future.

I am also sceptical that anyone will do anything to change the orthodoxy, either, which is a bit sad. Wegener’s theory of ‘continental drift’ was pooh-poohed by geologists almost everywhere, but a generation later (after his death) was resurrected as ‘plate tectonics’, and is now accepted as good theory. It may take a generation before ‘climate change’ theory is finally buried, at least in the form that humans are responsible for global climate. We’ll have something else to worry about by then, and I won’t be writing posts like this — or at all!


  • Walter Starck says:

    While at its core climate science was and is a “protoscience” it has been engulfed in a wave of “pseudoscience” which is now its public face. By any reasonable standard the untruths, deceptions, cherry picking, ignoring & suppression of conflicting evidence, personal denigration, logical inconsistencies and gross exaggerations which are now endemic to “climate science” must surely qualify it as a pseudoscience.

  • Doug says:

    To me the facts tells us we do not have an AGW problem and spending trillions to reduce CO2 emissions would not solve it if we did.

    As you say Don, CO2 does not act like a thermostat for the Earth. Like you, I am prepared to be convinced otherwise, but right now cannot see any evidence emerging that would do so. We are no longer dealing with facts, but politics, ideologies, vested interests etc and the type of behaviour Walter Starck outlines below.

    Meanwhile, there is still work to do. Last night’s TV news featured a huge solar farm at (I think) Walgett, that immediately evoked thoughts of Spain at its most irrational. I don’t recall a cost being mentioned, but it must have cost a packet. Any action against a repeat elsewhere would have my support, slight though it is.

  • Alan Gould says:

    Don, Doug, like you both, I am a provisional sceptic with regard to the AGW controversy, but Don, you address the idea of the sceptical mind generally, and I thought I’d lob in the view from the Poet’s angle.
    This is John Keats’ idea of ‘negative capability’ and was a part of that great Romantic energy at the cusp of the 18th/19th Centuries that sought to give imagination its place in the operations of mind beside Reason. Keats’ idea embraced a radical open-ness of mind, best summed up by his remark that ‘he never wanted to win an argument for fear that, by such a win, he excluded that portion of truth that might belong to his opponent’s case.’
    Naturally this has more application at the allusive end of existence rather than the defining end which Science and Maths take as their province. Though even here I would remind of the Heisenberg Idea of Uncertainty where the electron sometimes behaves like a particle and sometimes like a wave. Bronowski, in that wonderful TV series he made 40 years ago, preferred to call Heisenberg’s ‘Uncertainty’ the ‘Principle Of Tolerance’, suggesting that both interpretations for the electron (or the true position of a star etc) were true rather than one or the other. This does not subvert the idea of fact, but it does address the slipperiness of Reality when it comes to our human relationship with fact and truth.

  • David says:

    “There would need, for example, to be unequivocal evidence that ‘climate sensitivity’ was at the very high end of the IPCC’s range — 4.5, perhaps.”

    Don, not one is promising you “unequivocal evidence”. This is a child like or perhaps more accurately a septuagenarian’s expectation.

    Grown ups make decisions under conditions of uncertainty all the time.

    • Doug says:

      Only partly true David. Our decisions made under conditions of uncertainty are based on best knowledge and judgement of probabilities. Only when the knowledge and the probabilities support a particular action, as opposed to some other action, do we take that action.

      Twenty years of failed predictions strongly suggest that climate sensitivity related to CO2 has been seriously overstated, is not a problem and no action is needed. I would need unequivocal evidence of the contrary to change that view and to support the current expenditure of three billion dollars or more now occurring in Australia.

    • Don Aitkin says:

      Why? (Why not?) The whole AGW catastrophe scenario rests on climate sensitivity’s existing, and being very high. If it isn’t, there is nothing to worry about, at least in terms of greenhouse gases.

      Why do accept the AGW proposition, given the lack of evidence for it?

      • David says:


        Dance around your claim all you like. Your response only confirms my previous point. Assertion is no substitute for well reasoned argument.

        “unequivocal” -meaning “leaving no doubt; unambiguous”.

        Society makes decisions about all sorts of important issues without requiring that there be absolute certainty.

        • Don Aitkin says:


          Perhaps you could present some well-reasoned argument to show why my previous posts on climate sensitivity (http://donaitkin.com/climate-sensitivity-is-back/ , which contains a link to earlier ones) is flawed. I do my best to provide what what you ask for, and not just assert things. Of course you are right to say that society makes decisions without always being sure — indeed, you could have argued that it is never sure — but even you must wonder why in this case society makes decisions when the evidence is largely against the policy being advocated — as Doug has argued below..

          • David says:

            “Of course you are right to say that society makes decisions without always being sure”

            so don’t set the bar at “unequivocal evidence”. 🙂

          • Don Aitkin says:

            That was for me, not for society. But you are right in my case, too.

  • Don Aitkin says:

    A correspondent has offered the following, which I rather enjoyed:

    ‘When is Climate Change Science not a science?
    · When it appeals to the authority of consensus.
    · When it uses the ad hominem card against its sceptics.
    · When it says that “the science is settled” and “the debate is closed.”
    · When it promotes a theory that cannot be falsified.
    · When it is driven by a “confirmation bias”, reporting only findings that appear to support it and hiding those that don’t.
    · When it exaggerates the extent and dangers of climate change.
    · When it fails to acknowledge the uncertainties of the science.
    · When it refuses to acknowledge any positive aspects of climate change – like the benefits of rising CO2 levels and a greener world.
    · When it demonizes scepticism and lauds blind faith.
    · When it becomes dependent on Government support and fails to maintain a prudent separation of Science and State.
    A “science” that fails these ten basic tests begins to look suspiciously like The Church of Climatology rather than a science.

    • David says:

      Don, I know this is meant as a light hearted comment, but on what basis could it be argued that AGW cant be falsified?

      I thought the standard skeptic view was that AGW can be disproved, but the the socialist cabal at the ARC wont fund the required research, to look at sun spots, underwater volcanoes, wobbles in the earth’s orbit etc etc.

      • Don Aitkin says:

        I think that what was meant there is that AGW advocates do not accept falsification. Example, the critics show that there has been no warming for nearly twenty years, although the models all suggested that warming must follow from increasing CO2 accumulations. So the response is that the heat has disappeared into the deep oceans, which cannot at the moment be disproved. Or critics publish paper after paper that suggest that climate sensitivity is at the low end of the IPCC range, whereupon the response is to ignore them, as being flawed in one way or another. That comparable flaws apply with respect to papers suggesting a high end level of climate sensitivity is passed by.

        Climate science is largely observational, so that the normal test of hypotheses cannot be conducted through experiment. It may be that climate science is indeed a pseudoscience, though Popper would say not, arguing that just as Einstein’s theory of relativity superseded Newton’s theories in particular cases, then one day someone will find a way to supersede the current AGW orthodoxy.

        I hope that helps.

  • aert driessen says:

    A wonderful essay, re-assuring in its logic, gentle yet strong like an incoming tide in a sheltered bay. For me this sad state of affairs has many faces and draws on the less noble emotions woven into our consciousness- arrogance, greed, power, the fear of shame. As I see it this was probably started by good people with good intentions back in the 1980s. Then arrogance and greed beset some scientists (glory in discovering a new theory and research grants). Then the politicians saw it as a control mechanism and they literally hijacked and drove it, funding it with other people’s money. Now it has many faces in pursuit of power, ideologies (socialism), and greed (the Al Gores of this world). And the George Soros’ of this world are on the sidelines wrecking fossil fuel asset prices so that they can buy them at a discount. I am proud to be a sceptic as described here and I’m also a cynic, as you would have gathered by now.

    • Don Aitkin says:

      I think that the politicians recognised that the environmental thing was increasingly important within the electorate, and moved to try secure votes that way. And as I’ve said recently once people have committed themselves to something it’s hard for them to switch, especially when they are in the public gaze.

      • Alan Gould says:

        One of the saddest aspects of the AGW bird is that it is a cuckoo, namely a plump creature that flies into the nest, edges all its original occupants out, and hogs the space. So ironically, this big ‘environmental cause’ will serve to wreck the decent and more necessary things that arouse what should make us all environmentalists, namely care for the well-being of our home. There’s nowt wrong with wanting to fish that plastic out of the Pacific and restrain ourselves from fishinbg-out various whale and fish species. There’s nowt wrong with putting restraint on hacking down Amazon rainforest in the wanton manner we do, and avoiding the emission of lethals like cadmium into air or waters. Warmists moil these causes, qualifying themselves thereby to be the planet’s real polluters.

        • aert driessen says:

          I’m with you 110% Alan. And are you aware that even after suggestions and prompting, our clueless government will not put disposal bins for toxic materials (like Ni-Cd batteries (those small silver buttons) and those useless halogen? coiled light globes (I’m pretty sure that they contain a bit of Hg) in convenient locations like shopping malls? They expect me to drive to the Mitchell Recycling Depot to leave them there. I’m outing myself here by saying that I have decided not to drive to Mitchell but to chuck those spent items ion the yellow bin in the confident belief that advanced technologies (like powerful magnets) will pull those metals out of the stream of other recyclables. But a disposal bin at a shopping mall would be preferable and better.

      • aert driessen says:

        Thanks Don, I agree. Terms like ‘lowest common denominator’ and ‘weakest link’ also come to mind.

  • Margaret says:

    I really hope you (collectively), deigned to watch Q&A tonight. It was at its best. Tom Switzer and Naomi Klein on ‘climate change’ – fascinating to hear their perspectives and Tariq Ali a very fine person.

  • Google says:


    Usually posts some quite interesting stuff like this. If you?re new to this site.

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