Over at Watts Up With That?, Willis Eschenbach has written an interesting post entitled Some people claim, that there’s a human to blame …, regarding whether humans are responsible for the sharp rise in CO2 levels after 1850. He is upfront about his own personal view:
Let me preface this by saying that I do think that the recent increase in CO2 levels is due to human activities.
The strongest evidence for this view comes from the historical record, as it reveals an “excellent agreement between the eight different ice cores, including the different methods and different analysts for two of the cores.” Not only that, but there is also “excellent agreement between the ice cores and the Mauna Loa data,” which suggests that it “represents a good estimate of the historical background CO2 record,” although the possibility that the agreement is due to coincidence, conspiracy or simple error cannot be totally excluded. Willis Eschenbach then argues:
So if you are going to believe that this is not a result of human activities, it would help to answer the question of what else might have that effect. It is not necessary to provide an alternative hypothesis if you disbelieve that humans are the cause … but it would help your case.
A very sensible point. But what caught my eye was a comment by a reader who calls himself “Darkinbad the Brightdayler” (June 7, 2010 at 1:05 a.m.; the third response from the top), who objected to the word “believe” in the paragraph just cited:
I’m not comfortable with the use of the words “Believe” or “Disbelieve” in a scientific context. These words are more appropriate to discussions about religion and concepts which are not open to a process of proof.
To pull them into a scientific debate is to allow participants to think and respond in a less rigorous way than they ought.
So let me get this straight: holding a belief is unscientific? To my mind, that’s topsy-turvy thinking. Take away beliefs, and you destroy science.
Now, I’d like to be as fair as possible to Darkinbad the Brightdayler, so let me play devil’s advocate here. First, one might argue that science should be a completely dispassionate enterprise. If this is correct, then “scientific belief” is an oxymoron: scientists cannot test a hypothesis dispassionately if they believe in it, because believing that a hypothesis is true goes hand-in-hand with having a conviction that it is true. Disbelief is equally fatal to scientific objectivity, for the same reason.
On the other hand, once a hypothesis has been successfully validated by scientific testing, talk of “belief” or “disbelief” becomes even less relevant. For there is no need to believe something, once it has been demonstrated.
But if this account of science is correct, then we might reasonably ask: who needs scientists? For we could easily imagine a computer of the future, programmed to (i) randomly generate explanatory hypotheses for any surprising new data it encounters; (ii) test these hypotheses in accordance with standard scientific procedures; and (iii) update its data banks with those hypotheses that are validated by scientific testing. And if such a computer was able to maintain continuous electronic contact with an army of nanobots whose job it was to comb the world for new and unexpected phenomena, it would become the Ultimate Repository of scientific knowledge.
Right off the top of my head, I can think of at least three good reasons why this proposal wouldn’t work, however. First, even the random generation of a set of rival explanatory hypotheses presupposes the existence of a fixed number of parameters, whose value is allowed to vary. Let’s suppose there are N parameters. These parameters can then be used to generate a range of possible hypotheses, in N dimensions, which can be tested against each other. At the same time, however, the parameters limit the scope of the scientific investigation. So the larger question of how the parameters are chosen is one which requires a great deal of critical thinking – which is hardly the sort of thing that computers tend to excel at.
Second, standard scientific procedures are not etched in stone; they change over time, which means they need to be continually re-evaluated. How? It might seem that the best way for scientists to figure out what a good procedure is, is simply to do what they normally do: go out into the field and look at nature. However, the mere act of looking at nature cannot tell us how we should investigate nature. Observations, per se, don’t generate prescriptions. The question of what constitutes a good procedure for evaluating scientific hypotheses about the natural world is one which transcends the natural world itself. To answer that kind of question requires “out-of-the-box” critical thinking – thinking which is capable of scrutinizing each and every one of our cherished scientific concepts – and our meta-scientific concepts, as well – and rejecting them, if they do not withstand scrutiny. Human beings are the only beings in the cosmos, as far as we know, who are capable of this kind of thinking.
Third, critical thinking is needed to decide what counts as successful validation of a scientific hypothesis – and whether the definition of “validation” needs to be revised in the future.
You may ask: what’s the connection between critical thinking and belief? Simply this: someone who is capable of thinking critically is open to persuasion, which in turn produces conviction – a very Aristotelian point, by the way. For an entity that lacks a capacity for critical thinking cannot be persuaded of anything; hence it cannot properly be said to believe anything.
To recap: Darkinbad the Brightdayler’s belief-free model of science has the absurd entailment that humans (and other belief-holding entities) are not required to carry out the scientific enterprise; whereas I have argued for the view that without beings who are capable of holding beliefs, science could never proceed in the first place, as there would be no-one capable of defining what good science is.
However, Darkinbad the Brightdayler might respond: even if we grant that at any given time in history, the scientific enterprise necessarily presupposes the holding of certain beliefs about what “good science” is, these beliefs are not scientific beliefs. They are meta-scientific. We can kick them upstairs, as it were. Real scientists don’t worry about their beliefs while they’re doing their work; they just get on with testing their hypotheses and weeding out the bad ones.
But this is clearly inadequate as a model of what science is all about. To explain why, I’d like to illustrate with an example: Dr. Roy Spencer’s critique of the case for dangerous man-made global warming. Dr. Spencer contends that a confusion between forcing and feedback (loosely speaking, cause and effect) when observing cloud behavior has led to the illusion of a sensitive climate system; whereas satellite observations, he maintains, suggest that our climate system is insensitive to CO2 changes.
Obviously, I am in no position to comment on Dr. Spencer’s current hypothesis, that the Pacific Decadal Oscillation is behind much of the global warming which has occurred during the past 100 years. The point I wish to make here is that Dr. Spencer is clearly wearing his “critical thinking” cap while he does his science, and I applaud him for doing so. He is not just testing hypotheses; he is also thinking critically about them. To begin with, he is questioning the assumptions underlying a hypothesis which is currently in vogue (dangerous man-made global warming). Additionally, he is dealing with meta-scientific questions, while doing his science: what is the cause, and what is the effect, and how do we sort them out for climate systems? On top of that, he is asking what an observation which apparently confirms that hypothesis actually proves – could some other model account for the same observation, for instance? Finally, Dr. Spencer has constructed models suggesting that long-term climate changes can be caused by short-term random cloud variations, arguing that natural cycles could account for the warming observed in the past 50 years, and further contending that satellite observations, properly interpreted, point to our climate system being rather insensitive to atmospheric CO2 changes. Clearly, Dr. Spencer has an “alternative model” of how the Earth’s climate might work, and I think that it is fair to say that he tentatively believes in his model, but at the same time, he is fair-minded enough to acknowledge that the IPCC’s global warming hypothesis is a “plausible” one.
Whether Dr. Spencer is right or not, this is the kind of thinking we need for science to move forward as an enterprise. Dispassionate hypothesis-testing, by itself, will get us nowhere. Beliefs, far from discouraging scientific rigor, actually encourage it, for they can serve to sharpen scientists’ thinking whenever they engage in scientific debate. An encounter with scientists who hold opposing beliefs can force experts in a field to re-examine their cherished assumptions. It can also force them to “flesh out” their models in response to critical queries by other scientists.
I’d like to make one final observation in passing. I find it odd that Darkinbad the Brightdayler has suggested that beliefs are best relegated to “discussions about religion and concepts which are not open to a process of proof.” Darkinbad must surely realize that science does not deal in proofs; only mathematics does that. Since nothing in science is absolutely certain, the use of the term “belief” in a scientific context is perfectly apposite.
Darkinbad the Brightdayler’s post has had an unintended but beneficial result: it has generated a discussion about the nature of science itself – a discussion which my readers will hopefully continue, and apply to the Intelligent Design debate. For that, I would like to thank Darkinbad.
Willis Eschenbach has proposed some excellent Rules for Discussion at the end of his post, which I shall reproduce below, without further comment.
RULES FOR THE DISCUSSION OF ATTRIBUTION OF THE CO2 RISE
1. Numbers trump assertions. If you don’t provide numbers, you won’t get much traction.
2. Ad hominems are meaningless. Saying that some scientist is funded by big oil, or is a member of Greenpeace, or is a geologist rather than an atmospheric physicist, is meaningless. What is important is whether what they say is true or not. Focus on the claims and their veracity, not on the sources of the claims. Sources mean nothing.
3. Appeals to authority are equally meaningless. Who cares what the 12-member Board of the National Academy of Sciences says? Science isn’t run by a vote … thank goodness.
4. Make your cites specific. “The IPCC says …” is useless. “Chapter 7 of the IPCC AR4 says …” is useless. Cite us chapter and verse, specify page and paragraph. I don’t want to have to dig through an entire paper or an IPCC chapter to guess at which one line you are talking about.
5. QUOTE WHAT YOU DISAGREE WITH!!! I can’t stress this enough. Far too often, people attack something that another person hasn’t said. Quote their words, the exact words you think are mistaken, so we can all see if you have understood what they are saying.
6. NO PERSONAL ATTACKS!!! Repeat after me. No personal attacks. No “only a fool would believe …”. No “Are you crazy?”. No speculation about a person’s motives. No “deniers”, no “warmists”, no “econazis”, none of the above. Play nice.