Evident: Adjective: clearly seen or understood; obvious.

Late Middle English: from Old French, or from Latin evidens, evident- ‘obvious to the eye or mind’, from e- (variant of ex- ) ‘out’ + vident, past participle of videre ‘to see’.

You may recall that not so long ago I recounted for you the history of the fact. If so, you will know that the fact was born under the name factum and that after initially working tirelessly in the law courts it moved on to become quite the bee’s knees within the world of scientific discovery, only to then suffer a crisis of reputation as the whole world, egged on by the internet, would take its name in vain in the pursuit of personal influence and ideological advancement. Now I would like to shine the same biographical spotlight onto one of its closest associates: Evidence. For whilst the story of the fact may be one of rags to riches to sleaze, I have to say that the tale of the evident is no less problematic. When the factual lost its way, a lot of the blame lay with the decline in reliable support it was receiving from the evidential, and nowhere has this been more apparent than in the world of climate change science.

Brothers in Law

The evidential first became acquainted with the factual when they both met up in the law courts. Prior to that, the evident had a relatively minor role to play by designating things that were obvious to the eye (e vident). It was only after the evident came to be understood as something that was also obvious to the mind that it found ready work within the legal system [1]. As a result, the sight of blood could then be ‘seen’ as a sign of the factum.

Indeed, the facts of the matter could only become matters of fact through the support of their old buddy, evidence. And whilst it would have been nice if direct observation of the misdeeds could be brought to the attention of the jury, in practice a lot of the evidence would entail things that were, instead, supposedly obvious to the mind. The reality is that legal evidence comes in many forms and not all evidence carries the same weight as far as the courts are concerned. For that reason, experts in law have spent much time over the years classifying and evaluating evidence types so that some degree of objectivity might be brought to the bar [2]. It was, and remains, a tough gig, because once one loses actual sight of the deed and starts letting the mind do the seeing, subjectivity starts to take charge.

The court’s purpose, of course, is to establish a weight of evidence that can match the burden of proof and, if possible, do so in a quantified manner. But this, I’m afraid, entails a lot more than deciding how many expert opinions it takes to overrule a village idiot’s observations. First, one has to decide upon the admissibility of evidence. For the purposes of such an adjudication, the adduced evidence (this is legal jargon for ‘evidence presented to the court’) can be categorised as testimonial, documentary, artefact (such as a potential murder weapon) or demonstrative (such as a fingerprint). There are many reasons why such evidence may be so untrustworthy as to be considered inadmissible and I’m sure we have all seen enough episodes of Perry Mason to be familiar with them. No? Too young? Never mind. The point is that here we are mainly concerned with fidelity, i.e. whether the evidence is a true and reliable indicator.

Secondly, there is the question of justification, i.e. whether the weight and nature of the evidence is compelling enough to draw the conclusions necessary to construct a case. At this stage, all sorts of other considerations come into play, such as the degree of relevance, corroboration, and sufficiency. I’m no lawyer, and so I will not even attempt to lead you through all the intricacies of the legal issues involved here. Suffice to say, evidence can support facts and facts can be used as evidence, and the interplay can be so complex that evidence and fact are often mistaken for each other, much to everyone’s bemusement [3]. The only problem (which often goes overlooked) is that evidence isn’t too proud to rely heavily upon opinion, so the fact can often end up mixing with dodgy company without necessarily being aware.

A Career in Science

Given the incestuous relationship existing between fact and evidence, it wasn’t surprising that when the former moved on to pursue its scientific career the latter (in the garb of scientific evidence) would do the same. Unfortunately, the problems that had dogged our inseparable duo during their legal career just followed them into the world of science. New terminology such as ‘hypothesis’, ‘theory’ and ‘experiment’ became the vogue but the issues stayed the same. Today, the lawyer and the scientist may have different ways of going about their work, but there is no essential difference between their respective objectives. In both cases it is all about truth and justification: determine the truth but provide sufficient justification for believing that the truth has been uncovered. And in both cases the extent to which subjectivity and speculation are present influences the nature and weight of evidence. Nevertheless, there was plenty enough in the scientific method to deal with the problem. Experiment and field observation proved very handy in making things obvious to the eye and, when it came to those things that were supposed to be obvious to the mind, the concepts of relevance, corroboration and sufficiency were just as pertinent and effective in the scientific context as they had been in the courts.

The Importance of a Good Argument

To the extent that tales of statistical significance and the replication of experimental results can establish the e vident, science has always been on a firm footing, so much so that there would really be no need to create arguments akin to a legal case for a jury’s deliberations. However, when science encroaches upon territory where the mind rather than the eye is determining the obvious, the legal model starts to look more and more relevant. Such is the case with climate change science.

Looking at an IPCC Assessment Report, one cannot help but gain the impression that a case is being argued based upon a whole raft of evidence of varying quality, and that the reports are designed to allow policymakers to weigh up the evidence and to persuade them to arrive at a particular verdict. One would therefore hope that the argument would be presented in a clear, methodical and objective fashion that expounds upon how the evidence may be weighed and how the burden of proof has been met. One would also hope that the legal principle of balance would apply and that the jury would be allowed to draw its own conclusions based upon arguments for and against. But, of course, the IPCC has only ever been the brief for the prosecution. It has never been within the IPCC’s scope of duties to present counter-arguments [4]. And as for clarity and structured argument, I have to say that the average Assessment Report is something of a crock.

At this point I should explain how the IPCC could learn a great deal from the best practice of other disciplines faced with similar challenges; for example, I could point to best practice in the development of safety cases within the field of safety-related engineering. However, I’m going to leave that until another day. For now, all I’ll say is that it is a good job that the safety cases developed for the aeroplanes used by IPCC members to fly off to their conferences are a damned sight more clear and coherently structured than the reports that the IPCC is producing.

The Evident Gets Sloppy

Evidence’s big break came when it took on the additional role of specifying things that were to be obvious to the mind as well as to the eye, i.e. the point at which ‘seeing is believing’ was supplemented with ‘believing is seeing’. This extra freedom allowed it to feature in situations where one did not have direct ‘sight’ of what nature was up to. The mind could decide what was obvious rather than always having to rely on the e vident. And when the mind started to struggle, the computer model would step in to boost its ‘vision’. This was convenient since everything that could be reasoned could now be considered as evidence. But on the downside even propositions that were far from obvious could still be labelled as ‘evident’ – one only needed to find a sufficient number of minds to impress with plausible propositions. In a court, that number was twelve and the system works reasonably well, give or take the odd OJ Simpson. In climate science, the number ninety-seven seems popular but the system still works reasonably well, give or take the odd hockey stick and plenty more besides. Even so, ‘evident’ had learnt to oversell itself and it wasn’t too long before sceptics began to catch on.

See You in Court

It is common within the climate change debate to see healthy scepticism denounced using the epithet ‘denier’. This slur gets its potency from the fact that only the irrational would refuse to accept that which was obvious. There is much legitimacy in this criticism when the evidence concerned relates to things that are obvious to the eye but when so much of the evidence takes the form of things supposedly obvious to the mind, the concept of denial becomes a much more contentious issue. The fact that ‘denier’ is such a prevalent insult nowadays is testimony to the extent to which opinion has substituted for fact, and this in turn reflects the extent to which supposed facts are so often supported only by assertions that are purportedly obvious to the mind.

In order to bolster accusations of denial, a great deal of effort nowadays has been expended in portraying climate change as e vident. Apparently, one has only to look at extreme weather events to see with one’s own eyes the irrefutable sign of catastrophe in the making. So confident are some regarding this assertion that they are now willing to take it to court. That may be the moment of truth as far as climate change evidence is concerned. That may be the point at which the true extent of evidence’s decline in the hands of climate change science becomes apparent – because, far from being e vident, the whole thing will actually be settled on the testimony of the key character witness:

“I’m a climate model, Your Honour, and believe me when I say, this is just the sort of thing that anthropogenic climate change would do.”

Good luck with that one.

Notes

[1] The word video had a similar CV but had to wait an awful lot longer before it found employment in the courts.

[2] See, for example, Anderson, T., D. Schum and W. Twining, 2009, Analysis of Evidence, Cambridge: Cambridge University Press, 3^rd edition.

[3] To navigate through this maze you have to understand things like factum probans and factum probandum.

[4] In a document clarifying its role, the IPCC states, “Scientific understanding about the implications of a global temperature increase of 1.5ºC above pre-industrial levels is growing quickly”. So I think it is fair to say that the IPCC is not engaged in building the case for inaction.