Terry Pratchett - The Science of Discworld II - The Globe

He was arrogant and mystical. His saving grace was that he was also very bright. He placed great importance on using nature's own powers of healing. For example, letting wounds drain instead of padding them with moss or dried dung. He discovered that mercury was an effective treatment for syphilis, and his clinical description of that sexually transmitted disease was the best available.

The main objective for most alchemists was far more selfish, sights were set on just one thing: transmuting base metals like lead into gold. Again, their belief that this was possible rested on a story. They knew from their experiments that sal ammoniac and other substances could change the colour of metals, so the story 'Metals can be transmuted' gained ground. Why, then, should it not be possible to start with lead, add the right substance, and end up with gold? The story seemed compelling; all that they lacked was the right substance. They called it the Philosopher's Stone.

The search for the Philosopher's Stone, or rumours that it had been found, got several alchemists into trouble. Noble gold was the prerogative of the nobility. While the various kings and princes wouldn't have minded getting their hands on an inexhaustible supply of gold, they didn't want their rivals to beat them to it. Even searching for the Philosopher's Stone could be considered subversive, just as searching for a cheap source of renewable energy now is apparently considered subversive by oil corporations and nuclear energy companies. In 1595 Dee’s companion Edward Kelley was imprisoned by Rudolf II and died trying to escape, and in 1603

Christian II of Saxony imprisoned and tortured the Scottish alchemist Alexander Seton. A dangerous thing, a clever man.

The story of the Philosopher's Stone never reached its climax, alchemists never did turn lead into gold. But the story took a long time to die. Even around 1700, Isaac Newton still thought it was worth having a go, and the idea of turning lead into gold by chemical means was finally killed off only in the nineteenth century. Nuclear reactions, mind you, are another matter: the transmutation can be done, but is wildly uneconomic. And unless you're very careful, the gold is radioactive (although, of course, this will keep the money circulating quickly, and we might see a sudden upsurge of philanthropy). How did we get from alchemy to radioactivity? The pivotal period of Western history was the Renaissance, roughly spanning the fifteenth and sixteenth centuries, when ideas imported from the Arab world collided with Greek philosophy and mathematics, and Roman artisanship and engineering, leading to a sudden flowering of the arts and the birth of what we now call science. During the Renaissance, we learned to tell new stories about ourselves and the world. And those stories changed both.

In order to understand how this happened, we must come to grips with the real Renaissance mentality, not the popular view of a 'Renaissance man'. By that phrase, we mean a person with expertise in many areas -like Roundworld's Leonardo da Vinci, who bears a suspicious resemblance to the Disc's Leonard of Quirm. We use this phrase because we contrast such people with what we call a 'well-educated' person today.

In medieval Europe, and indeed long after that, the aristocracy considered 'education' to mean classical knowledge -the culture of the Greeks -plus a lot of religion, and not much else. The king was expected to be well informed about poetry, drama and philosophy, but he wasn't expected to know about plumbing or brickwork. Some kings did in fact get rather interested in astronomy and science, either out of intellectual interest or the realisation that technology is power, but that wasn't part of the normal royal curriculum.

This view of education implied that the classics were all the validated knowledge that an 'educated' person needed, a view not far from that of many English 'public' schools until quite recently, and of the politicians they have produced. This view of what was needed by the rulers contrasted with what was needed by the children of the peasantry (artisan skills and, lately, the 'three Rs' [20] Headers who have not met this felicitous phrase, for reasons of youth or geography, should be told that the three Rs are Reading, Riting and Rithmetic. What this tells us about the educational establishment is unclear, but it could be a joke. The three Rs, not the educational establishment, that is. Though, come to think of it... ).

Neither the classics nor the three Rs formed the basis for the genuine Renaissance man, who sought a fusion of those two worlds. Pointing to the artisan as a source of worldly experience, of knowledge of the material world and its tools such as an alchemist might use, led to a new rapprochement between the classical and the empirical, between intellect and experience. The actions of such men as Dee, even those of the occultist Paracelsus in his medical prescriptions emphasised this distinction, and started the fusion of reason and empiricism that so impresses us today.

As we've said, the word 'Renaissance' refers not just to rebirth, but to a specific rebirth, that of ancient Greek culture. This, however, is a modern view, based on a mistaken view of the Greeks, and of the Renaissance itself. In 'classical' education, no attention is paid to engineering. Of course not. Greek culture ran on pure intellect, poetry an philosophy. They didn't have engineers.

Oh, but they did. Archimedes constructed great cranes that could lift enemy ships out of the water, and we still don't know exactly how he did it. Hero of Alexandria (roughly contemporary with Jesus) wrote many texts about engines and machines of various kinds of the previous three hundred years, many of which show that prototypes may have been made. His coin-operated machines were not too different from those that could be found on any city street in 1930s London or New York, and would probably have been more reliable when it came to disgorging the chocolate, if the Greeks had known about chocolate. The Greeks had elevators, too.

The problem here is that information about the technical aspects of Greek society has been transmitted to us through a bunch of theologians. They liked Hero's steam engine, and indeed many of them have a little glass one on their desk, a sort of Theologians' Toy that they could spin with a candle flame. But the mechanical ideas behind such toys just passed them by. And, just as Greek engineering has not been transmitted to us by theologians, the spiritual attitude of the Renaissance has not come down to us through our 'rational' school teachers. Much of the attempted spirituality within the alchemical position was basically a religious stance, marvelling at the Works of the Lord as they were exposed by the marvels of changes of state an form, when materials were subjected to heat, to 'percussion', and to solution and crystallisation.

This stance has been taken over by today's innocents of rigorous thinking, the New Agers, who find spiritual inspiration in crystals and anodised metals, spherical spark-machines and Newton's pendulums, but do not ask the deeper questions that lie behind these toys. We find the very real awe inspired by science's quest for understanding to be considerably more spiritual than New Age attitudes.

Today there are mystic massage-therapists, aromatherapists, iridologists, people who believe that you can 'holistically' tell what's wrong with someone by examining their irises or the balls of their feet -only -and who root their beliefs in the writings of Renaissance eccentrics like Paracelsus and Dee. But those men would have been horrified to be cited as authorities, especially by such closed-minded descendants.

Prominent among those who refer back to Paracelsus for authority are homeopathists. A basic belief of homeopathy is that medicines become more powerful the more they are diluted. This stance lets them promote their medicine as being totally harmless (it's just water) but also extraordinarily effective (as water isn't). They notice no contradiction here. And homeopathic headache tablets say 'Take one if mild, three if painful'. Shouldn't it be the other way round?