What is truth? Part 1: Science and Statistics

by Vincent Guy



S. Q. Field, Gut Reactions, Chicago Review Press 2019

What is truth? said jesting Pilate, and would not stay for an answer.

Francis Bacon, 1601


Bacon’s line suggests that the Roman governor was in the same mood as when he later washed his hands. But both Bacon and Pilate come across as rather enigmatic. Bacon went on to become the founding father of the scientific method, champion of the inductive approach, which means, in short, basing your knowledge on clear observable facts.

Today Pilate’s question is more pressing than ever. We live in an era of post-truth, fake news, Meghan Markle’s “my truth”, and the myriad deniers of evolution, vaccination, and science itself.


Science

Does science offer us truth? As Patrick Vallance, UK Chief Scientific Officer, tells us: “Science is all about uncertainty”. In essence, the scientific method is doubt: never take anything on trust, keep asking how certain you are and, if your predictions are not borne out by experiments, abandon them.


It’s not an easy path.


Agustín Fuentes, an anthropologist, so a social scientist, offers to help us towards truth in his book Race, monogamy and other lies they told you (2012). As the title indicates, it’s aimed at a lay audience. But already in the early pages he tells us we must have a thorough understanding of genetics, including gene flow and genetic drift. I’m a non-scientist who has cast an inquiring eye into books on genetics ever since Watson’s The Double Helix (1968). Though I’ve come across these terms, I have only a confused grasp of their meaning.

What about diet? Relevant to everyone’s daily life, it’s an ever-shifting field: eggs are bad, then they’re good again; avoid coffee, no, have some every day; cut out fat, no, you need it. And cholesterol good and bad: do you know the difference? In Gut Reactions: the science of weight gain and loss, Professor S.Q. Field brings a chemist’s expertise to bear, but within a few pages you’ll be struggling with dozens of terms you’ve never heard before: AGRP, ghrelin, beige fat….. Will the diagram above help you?


In my hands is a book about the structure of our bodies. That it’s meant for youngsters is indicated by the title: Dr Frankenstein’s Human Body Book: the monstrous truth about the human body (2008). While the pictures are powerful and informative, a glance at the text sets your head spinning with unfamiliar vocab: Cytoplasm, Endoplasmic reticulum, Epithelial tissue, Periosteum, Osteon, Osteocytes…etc, etc. In a 90-page book consisting mostly of illustrations, I found 50 terms I’d never met before in my life. There’s a glossary, but most of these words aren’t there.


The truth is complicated and elusive; simplifying it is far from easy.


Don’t get me wrong - these books have much of value: that males and females overlap in mind and body, that fasting is more effective than dieting, even the broad point that the body’s workings are immensely complex.


Let’s take a look at the bigger picture. Two writers in the 20th century, Karl Popper and Thomas Kuhn, both suggested that science is not a fixed framework of certain knowledge, but constantly on the move.


Popper’s approach is neatly expressed in the title of one of his books: Conjectures & Refutations (1963). A scientist gets an idea and then tests it by experiments and observations. And if other scientists can repeat those experiments getting similar results, the conjecture is confirmed. Science is thus a network of interlocking interpretations of the world moving steadily forwards.


For Kuhn in The Structure of Scientific Revolutions (1962), at any given moment there is an overarching paradigm, Newton’s laws of motion, say, or evolution by natural selection. This holds sway until new experiments and new data reveal its flaws and a new paradigm takes over – a paradigm shift. For example, the positive role of gut bacteria has now replaced the idea that all bacteria are harmful. So, if Popper sees science as something like a slime mould spreading and probing on many fronts, for Kuhn it is more like an ice sheet that cracks from time to time to be refrozen in a new way. My own view favours Popper though his approach has of course been refined and surpassed since he wrote.


The best book on scientific truth I’ve come across recently is Nonsense on Stilts by Massimo Pigliucci (2010). It’s elegantly written, wide-ranging, even has some good jokes. He neatly encapsulates the main point of this article: “the nature of science is not that of a steady linear progression towards the truth, but rather a tortuous road, often characterised by dead-ends and U -turns, and yet ultimately inching towards a better, if tentative, understanding of the natural world”.


Statistics

Statistics are a vital tool in science, economics, and even in daily life. But we must be cautious. After all, as Disraeli said, “There are lies, damned lies, and statistics”.


Did he though? A little digging reveals that it was Mark Twain who popularised the phrase and it might even go back to the Duke of Wellington. A version by T. H. Huxley, Darwin’s bulldog, runs “Liars, damned liars and experts”, a thought echoed in the recent Brexit debates.


At the start of the Covid era, I tried to get a handle on the international statistics that were buzzing around. My intention was to penetrate the undergrowth of numbers by concentrating on figures for deaths in each country - clear indubitable facts. It didn’t take me long to discover that several countries were indeed lying, others making substantial inadvertent errors. In any case, each country was using different methods of counting, labelling, and recording. I gave up, leaving things to the above-mentioned experts.


There’s a technique in statistics known as the Bayesian approach. My grasp of mathematics is not up to using it, yet alone explaining it to readers. But in essence it’s a way of building the enquirer’s assumptions into the calculations from the start. Results are greatly strengthened. Perhaps not far from the naïve approach “Do the figures look right?”


The words Truth and Trust share common etymological roots. We cannot know everything. We must take many things on trust. But we must probe and test and weigh up before bestowing that trust. Professor Sir David Spiegelhalter, former President of the Royal Statistical Society, put it thus:

Trust is the crucial thing… We do have to trust; we can’t check everything for ourselves, we can’t do our own research. We have to identify trustworthy sources.” He was speaking on that rich, if seldom cited, source of academic insight, Desert Island Discs.


As a trained surgeon, John Keats was one of the few great poets with a scientific background. In Ode on a Grecian Urn (1819), he gives his view on our question. While enigmatic, it is certainly beautiful and, by his logic, must also be true:


Beauty is Truth, Truth Beauty:

That is all ye know

and all ye need to know.”

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