Welcome Friend to this my first Commentary, inspired by the ideals of the Roman orator Marcus Fabius Quintilius.
Nullius in verba is the time-honoured motto of the Royal Society of London. It has generally been taken to mean "take no one's word for it". It originated from the early days of the Society, at a time when learned discussion was dominated by opinion, assertion and cultural conditioning, rather than being led by empirical evidence. The founders of the Society wanted to establish scientific debate on a better footing than on just assertion and opinion. But note: the motto does not tell us not to listen to people, but it cautions us against automatically accepting what they say as true.
It is a motto which should be kept in mind not only in scientific debate but in the nornal flow of our lives.We are bombarded constantly with baseless assertions from politicians, journalists, fashion advisors, advertisers, religious bigots and suchlike. This includes bloggers. We are well advised to listen to their pronouncements with a critical ear. And yes, I include myself in the list. Don't take my word for anything but judge for yourself. And be sure to apply the motto to yourself: try to avoid giving baseless opinions.
So why am I writing about this old topic? Well, it has been in the news recently on account of the debate about global warming. It appears that there is a row between some members of the Royal Society and some sections of the Press about the interpretation of "Nullius in verba". Some journalists and bloggers suspect undue pressure is being put on those scientists who do not fully accept the "evidence" about global warming being caused by human activity. It looks to them like an establishment conspiracy.
Conspiracy theories are very unpleasant. They can condition you to think the universe is run by aliens trying to make you do crazy things. So I am always wary of any conspiracy theories. They are usually based on blanket assertions which, once accepted, are used to make people believe all sorts of nonsense.
My problem with the global warming debate is not whether it's caused by humans or not. It's with the nature of evidence. I think too many people don't understand the difference between data and information (I regard "information" and "evidence" as virtual synonyms). Data is simply a collection of responses in detectors, such as clicks in photon counters in quantum optics experiments, or a graph of distance dropped in a gravitational field over time. Information is the interpretation of that data.
(Addendum: I am well aware that there are numerous subtle questions here, such as: how do we define data without some prior concepts, i.e., is the concept of data an absolute one? I will discuss such points in future Commentaries)
The point is, interpretation requires an observer with some preconceived model, or theory, or paradigm, which is used to fit the data. For example, consider the data that someone has just been killed by a lightning strike in a field. If we were an ancient Greek, we would interpret that as evidence that Zeus exists and had expressed his displeasure. If we were a student of classical Maxwellian electrodynamics, we would say that a cloud had discharged a surplus of electric charge through the air and through that person. If we were a twentieth century elementary particle theorist, we might say that electrons had passed through a region of Minkowski spacetime containing non-trivial abelian gauge fields, following a path of maximum Feynman quantum path probability (sorry, I got rather carried away here).
I hope you see what I mean. Data is not evidence. Nullius in verba warns us not to confuse the two. So when some people at the Royal Society say that all the evidence points to global warming being caused by humans, I am a bit worried. The data may be good, but the interpretation of that data might not be so good. What is evidence to you might not be evidence to me. It's bad science to do what some people at the Royal Society have done, which is to say that the current climate data is evidence for their position, and then go on to accuse their opponents of disbelieving "the" evidence. Good science requires scientists to constantly question their own interpretation of data, not only the interpretations of their opponents.
I should add that we should not believe that all interpretations have equal validity. In science, an acceptable interpretation has to pass a reasonable standard of objectivity, which requires careful examination of its basic assumptions and then further testing of its predictions. In the climate debate, for instance, I think it is too early to say for sure that the current rise in temperature is wholly caused by human activity. It could be contributed to by factors other than human industrial activity, such as Ocean Circulation, Volcanic Eruptions, Solar Variations, and Orbital Variations. There have been many ice-ages, with repeated global warming and cooling. So I would keep other possible causes in mind, as well as the popular "caused by humans" assertion. But I would certainly not consider for a second any "explanation" which asserted that global warming was punishment by God for our sins.
The correct way to discuss such issues is to assign probability estimates for each assertion, along with an indication of confidence in that estimate. So for example, we might say that we thought it was more than likely that humans are the main cause of global warming, and that we thought it unlikely that new evidence would change that estimate much. This is the "Establishment" view currently, and there is nothing wrong in presenting it that way. So, applying this approach to the "God" explanation mentioned above, I am prepared to say that I believe there is zero chance that it is correct, and I don't expect any new evidence soon to make me change my mind. In fact, I would be delighted if such evidence did appear (but of course it will not).
As for scientists arguing visciously amongst themselves, that is a poor and disreputable way to do science. Science should not involve browbeating opponents or putting undue pressure on them to conform. Respect your opponents if they are following the scientific method honestly, even if you think they are wrong. Rational debate based on verifiable data is always the best way. History shows that in the long run, bad science always gets exposed, even if sometimes it looks as if the charletans appear to be winning (I plan to blog on superstring theory presently). It is useful here to remember the Lysenko controversy: (quote from Wikipedia: "Lysenkoism is used colloquially to describe the manipulation or distortion of the scientific process as a way to reach a predetermined conclusion as dictated by an ideological bias, often related to social or political objectives.")
This brings us to another subtle and sensitive row, again involving the Royal Society. In 2008, the Society's director of education Michael Reiss, a biologist and ordained Church of England clergyman, stepped down from that position in the Society after other members had taken exception to his public comments on Creationism. Were these critics being fair? What is wrong with his position, which was that there should be an intelligent debate on the subject?
Nullius in verba can help us here. In the climate debate, we can go out and test data against the solar heating theory, or against the volcanic eruption theory, and so on. We simply can't do that with the "God is punishing us" assertion. So, in the case of Creationism, we give it a zero and ignore it as a scientific concept, simply because there is no way we can test it. Apart from that, I would always naturally suspect the motives of any scientist who was an ordained minister and who tried to introduce a theological concept into science. It smacks too much of Lysenkoism to me.
This raises a fundamental question: are there any absolute truths in science? (Or anywhere, for that matter) I will discuss this question in my next Commentary. It does have an answer, but you might not like it: it could challenge the way you have been conditioned to think.
Marcus Fabius Quintilian
