Terry Pratchett - The Science of Discworld II - The Globe

In Figments of Reality we included a chapter with the title 'We wanted to have a chapter on free will but we decided not to, so here it is'. There we examined such issues as whether, in a world without genuine free will, it would be fair to blame a person for their actions. We conclude that in a world without genuine free will, there might not be any choice: they would get blamed anyway because the possibility of them not being blamed did not exist.

We won't go over that ground in detail, but we do want to summarise the main thrust of the argument. We start by observing that there is no effective scientific test for free will. You can't run the universe again, with everything exactly as it was, and see if a different choice can be made second time round. Moreover, there seems to be no room in the laws of physics for genuine free will. Quantum indeterminacy, seized on so readily by many philosophers and scientists as a catch-all explanation of 'consciousness', is the wrong kind of thing altogether: random unpredictability is not the same as choosing between clear alternatives.

There are many ways in which the known laws of physics could offer an illusion of free will, for example by exploiting chaos or emergence, but there is no way to set up a system that could make different choices even though every particle in the universe, including those making up the system, is in the same state on both occasions.

Add to this one rather interesting aspect of human social behaviour: although we feel as if we have free will, we don't act as if we believe that anybody else has. When somebody does something uncharacteristic, 'not like them', we don't say 'Oh, Fred is exercising his free will. He's been a lot happier since he smiled at the tall, dark stranger.' We say 'What the devil has got into Fred?' Only when we find a reason for his actions, an explanation not involving the exercise of free will (like drunkenness, or 'doing it for a bet') do we feel satisfied.

All of this suggests that our minds do not actually make choices: they make judgements. Those judgements reveal not what we have chosen, but what kind of mind we possess. 'Well, I never would have guessed,' we say, and feel we've learned something that we can use in future dealings with that person.

So what about that strong feeling that we get, of making a choice? That's not what we're doing, it's what it feels like to us when we're doing it, just as that vivid grey quale of the visual system is not actually out there on the elephant, but an added decoration that exists in our heads.

'Choosing' is what our minds feel like from inside when they're judging between alternatives.

Free will is not a real attribute of human beings at all: it is merely the quale of judgement.

People believed that elves could look like anything they wanted to, but this was, strictly speaking, wrong. Elves looked the same all the time (rather dull and grey, with large eyes, rather similar to bushbabies without the charm) but they could, without effort, cause others to see them differently.

Currently the Queen looked like a fashionable lady of the time, in black lace, sparkling here and there with diamonds. Only with a hand over one eye and extreme concentration could even a trained wizard dimly see the true nature of the elf, and even then his eye would water alarmingly.

Nevertheless, the wizards stood up when she entered. There's such a thing as courtesy, after all.

'Welcome to my world, gentlemen,' said the Queen, sitting down. Behind her, a couple of guards took up station either side of the door. 'Ours!' snarled the Dean. 'It's our world!'

'Let us continue to disagree, shall we?' said the Queen brightly. 'You may have constructed it, but it's our world now.'

'We have iron, you know,' said Ridcully. 'Would you like some tea, by the way? Foul stuff made without actual tea.'

'Much good may it do you. No, thank you,' said the Queen. 'Please note that my guards are human. So is your host. The Dean looks angry. 'You intend to fight here? When you have no magic? Be serious, gentlemen. You should be grateful, after all. This is a world without narrativium. Your strange humans were monkeys without stories. They did not know how the world was supposed to go. We gave them stories, and made them people.'

'You gave them gods and monsters,' said Ridcully. 'Stuff that stops people thinking straight.

Superstitions. Demons. Unicorns. Bogeymen.'

'You have bogeymen on your world, don't you?' said the Queen.

'Yes, we do. But outside, where we can get at 'em. They ain't stories. When you can see 'em, they don't have any power.'

'Like unicorns,' said the Lecturer in Recent Runes. 'When you meet one, you find out it's just a big sweaty horse. Looks nice, smells horsey.'

'And it's magical,' said the Queen, her eyes gleaming.

'Yes, but that's just another thing about it,' said Ridcully. 'Big, sweaty, magical. There's nothing mysterious about it. You just learn the rules.'

'But surely you should be pleased!' said the Queen, her eyes saying that she knew they weren't and was glad of it. 'Everyone here thinks this world is just like yours! Many people even believe that it is flat!'

'Yes, but back home they'd be right,' said Ridcully. 'Here they're just ignorant.'

'Well, there is not a single thing you can do about it,' said the Queen. 'This is our world, Mister Wizard. It's all stories. The religions here ... amazing! And the beliefs ... wonderful! The crop is bountiful, the harvest is rewarding. Do you know that more people believe in magic here than they do on your world?'

'We don't have to believe in it. It works!' snapped Ridcully.

'They believe in it here, and it doesn't,' said the Queen. 'And thus they believe in it even more, while ceasing to believe in themselves. Isn't it astonishing?'

She stood up. Most of the wizards went to stand up, too, and one or two of them got all the way.

Misogynists to a man, the wizards were therefore always punctiliously polite to ladies.

Here, you are just rather fussy old men,' she said. 'But we understand this world and we have had time to cultivate it. We like it. You can't take us away. Your humans need us. We are part of their world now.'

'This world, madam, has about another thousand years before all life is wiped out,' said Ridcully.

'Then there are other worlds,' said the Queen, lightly.

'That's all you have to say?'

'What else is there? Worlds begin and end,' said the Queen. 'That is how the universe works. That is the great circle of existence.'

'The great circle of existence, madam, can eat my underwear!' said Ridcully.

'Fine words,' said the Queen. 'You are good at concealing your true thoughts from me, but I can also see them in your face, nevertheless. You think you can still fight us and win. You have forgotten that there is no narrativium in this world. It does not know how stories should go.

Here, the third son of a king is probably just a useless weak prince. Here, there are no heroes, only degrees of villainy. An old lady gathering wood in the forest is just an old lady and not, as in your world, almost certainly a witch. Oh, there is a belief in witches. But a witch here is merely a method of ridding society of burdensome old ladies and an inexpensive way of keeping the fire going all night. Here, gentlemen, good does not ultimately triumph at the expense of a few bruises and a non-threatening shoulder wound. Here, evil is generally defeated by a more organised kind of evil. My world, gentlemen. Not yours. Good day to you.'

And then she was gone.

The wizards sat down again. Outside, the carriage rattled away.

'Quite well spoken for an elf, I thought,' said the Lecturer in Recent Runes. 'Good turn of phrase.'