The Science of Discworld IV Judgement Da - By Terry Pratchett, Ian Stewart Page 0,34

material world, one (Prior Analytics) was about the mind, and the other three (Posterior Analytics, Topics and Sophistical Refutations) were about law and argument. The essay that joined up mind and matter, De Anima – Life, or Soul – was not translated until the thirteenth century, so it got left out of the western world’s traditional ‘works of Aristotle’ for a thousand years, based entirely on Boethius. It was, in fact, translated from the Arabic in 1352 by Jean Buridan; all the great libraries then were in Arabia and Spain, and the Muslim religion was in the ascendant. But despite that, it was not then added to the standard ‘works of Aristotle’.

In particular, Descartes had access to Categories and On Interpretation, but not to De Anima or On Sense and the Sensible, which provided a series of beautiful bridges between mind and body. So, believing himself to be free from preconceptions, but in fact carrying only part of Aristotle’s weighty arguments in his memory, he divided mind from matter. That laid a secure foundation for this intellectual separation, right up to Norbert Weiner and Cybernetics, when feedback and machinery met.

That accident, that De Anima was not available to Descartes, or to Francis Bacon when he published the Novum Organon in 1620, which was based on the six essays translated by Boethius, changed the whole European intellectual climate for the next four hundred years. From Newton through to Einstein, physics was delimited with no thought of information. Shakespeare, Samuel Taylor Coleridge, all the way to Kingsley Amis, John Betjeman and Philip Larkin – everyone talked about machinery and industry, but only from outside.

The two worlds, mind and matter, only began to come together with Sigmund Freud and Carl Jung, who were in neither world, nor by any means in both. And then, after the Second World War, during which many scientists had been involved with communication issues, Claude Shannon began to publish papers in which information was treated as a quantitative concept. Soon after that came cybernetics, in which feedback of information interacted with amplification and other physical changes, resulting in changes to output. The safety-valve on a boiler was an early example: when the pressure got too high the valve released some steam. Weiner added room thermostats, which turned the heat off and on. Nearly all amplifiers for sound use ‘feedback’ to send the output back to the input, improving the sound quality.

Here information is used to control mechanical systems, which introduces a whole new dimension of technological magic. Hidden inside every laptop, iPhone, and for that matter, refrigerator, is a long, complex series of ‘spells’: the software instructions that make all of the general-purpose electronics carry out the specific tasks needed to make the gadget work. Programmers are today’s sorcerers.

However, no one yet thought of linguistics as having anything to do with that kind of information. Only at the turn of the millennium did Steven Pinker, a linguistic psychologist, write How the Mind Works from a neurological and linguistic viewpoint. The two sides met, productively, after three hundred and fifty years.

Pinker later wrote The Better Angels of our Nature, arguing that today’s humans are significantly less violent than they used to be. The book presents a wealth of data to support this contention. Nearly all of the reviews disagree; all of these are by people who are statistics-blind. They comment on the very apparent decline of violence in the last few centuries as if it were only apparent, unsupported by valid observations. Almost none of the comments are from positions that are modern and balanced; nearly all are from arts or science viewpoints, but not both.

Now that the division between mind and matter has been buried, or at least is on its way to the cemetery, how do we think about causality? Well, here is our second example, which splits into three related issues: day and night, the rainbow, and turning a light switch on.

What causes day and night? The answer is easy and obvious.fn2 It is a question of gravitational forces, working according to the law of gravity, and the Earth turning on its axis so that it presents different faces towards the Sun. The Earth turning, about once per twenty-four hours, is what causes day and night. Easy.

Now let’s think about a rainbow. Here things are a little more complicated. Jack sent each of his six children in to school to ask the teacher what made a rainbow. In each case the teacher gave what we’ve elsewhere