WHEN CHARLES MOORE was editing The Spectator he once asked me why, of his contributors, it was those trained in science who were the least honest. Most contributors respected truth but articles from people trained in science (medical doctors were the worst) would often provoke letters to complain of factual errors.

Charles Moore had supposed that scientists would revere facts, but that supposition is a myth: scientists actually treat facts the way barristers treat hostile witnesses — with suspicion.

The mythmaker was Karl Popper. Popper was not a scientist but a political philosopher who proposed that science works by “falsifiability”: scientists discover facts; they create a theory to explain them; and the theory is accepted until it is falsified by the discovery of incompatible facts that then inspire a new theory. Popper needed “falsifiability” to attack his enemies, namely Marx and Freud (and by extension the fascist apologists). Those writers claimed to be scientists but they made statements that could not be falsified by empirical testing: Freud might assert that, in our minds, an ego mediates between an id and a superego, but because those entities are subconscious their existence cannot be tested. Popper said, therefore, that Freud’s assertion was not scientific and was thus invalid.

Yet it is a myth that working scientists always respect falsifiability. Scientists often ignore inconvenient findings. Consider Copernicus. He moved the Earth from the centre of the universe, but he didn’t put the Sun there to fit the observations — because he “knew” that God preferred circular orbits to convoluted circles within circles.

Scientists still ignore facts. Consider the environment. All scientists “know” that industrialisation destroys it, but in 2001 Bjorn Lomborg wrote The Skeptical Environmentalist to reveal otherwise: the facts show that it is the poor countries that destroy the environment while the industrialised ones protect it.

Lomborg is Danish, so, faced with his inconvenient facts, Denmark’s Committee on Scientific Dishonesty condemned Lomborg for “dishonesty” and for flouting “good scientific practice”. But the Danish Ministry of Science has now vindicated Lomborg and condemned the committee for “unsatisfactory and emotional conduct deserving of criticism”.

Such argy-bargy is inevitable because scientists prize paradigms. Like Pontius Pilate asking what is truth, they know how disputable many facts really are; so the best scientists are poets, creating theories they seek to verify in the face of inconvenient observations. For a description of science as it is actually practised, read Alan Chalmers’s What is this Thing Called Science?

• WAS POPPER, moreover, fair to Freud? Might the id, ego and superego be detectable? A provisional answer emerges from a study by Samuel McClure, a psychologist at Princeton, of the irrational decisions his students make when tempted by immediate gratification.

  McClure offered his students certain choices (which I shall simplify). They could receive, after four weeks’ wait, an amazon.com voucher worth $20. But if they waited four weeks and a day the voucher would be worth $21. Sensibly, most students opted for the larger, delayed voucher. Yet if McClure offered his students a voucher for $20 today or $21 tomorrow, they were greedy and opted for immediate gratification.

  To study the students’ thinking, McClure looked at their brains using magnetic resonance, and he found that when they made rational decisions they used parts of the brain that are unique to the human being and that evolved recently. But when succumbing to impatience, they used a primitive part of the brain that we share with the brute animals.

  When we make greedy decisions, moreover, the rational parts of our brain try to overrule them — so struggling dieters will lament “a moment on the lips, a lifetime on the hips” even as they succumb to more pie — and McClure can follow the battles between the sensible and non-sensible parts of the brain on his scanners.

  McClure may indeed be mapping the battles between Freud’s id (short-term greed) and superego (long-term sanity) mediated by the ego. Perhaps Freud really was a scientist and perhaps Popper was doubly misled.

  The author is a clinical biochemist and Vice-Chancellor of the University of Buckingham

Times Recommends

• In the real world, the public sector must pay
• Playing politics in a land of double Dutch
• Be like the plinth people: not set in stone