The Year of Rice and Salt

'You see?' Iwang said. 'You can do it with balls of unequal size or the same size, it doesn't matter. Everything falls at the same rate, except if it is so light and broad, like a feather, that it floats down on the air.'

Khalid tried it again.

Iwang said, 'So much for Aristotle.'

'Well,' said Khalid, looking at the balls, then lofting them in his left hand. 'He could be wrong about this and right about other things.'

'No doubt. But everything he says has to be tested, if you ask me, and also compared with what Hsing Ho and Al Razi say, and the Hindus. Demonstrated to be true or false, in the full light of day.'

Khalid was nodding. 'I would have some questions, I admit.'

Iwang gestured at the alchemical equipment in the yard. 'It's the same for all this – you could test them, see what's useful and what's not.'

Khalid frowned. Iwang returned his attention to the falling balls. The two men dropped a number of different items from the device, chattering away all the while.

'Look, something has to be bringing them down,' Khalid said at one point. 'Bringing them, forcing them, drawing them, what have you.'

'Of course,' said Iwang. 'Things happen by causes. An attraction must be caused by an agent, acting according to certain laws. What the agent might be, however…'

'But this is true of everything,' Khalid said, muttering. 'We know nothing, that's what it comes down to. We live in darkness.'

'Too many conjoined factors,' Iwang said.

Khalid nodded, hefting a carved block of ironwood in his hand. 'I'm tired of it, though.'

'So we try things. You do something, you get something else. It looks like a causal chain. Describable as a logical sequence, even as a mathematical operation. So that you might say, reality manifests itself thus. Without worrying too much about defining what force it is.'

'Perhaps love is the force,' Bahram offered. 'The same attraction as of persons to persons, extended between things in a general way.'

'It would explain how one's member rises away from the Earth,' Iwang said with a smile.

Bahram laughed, but Khalid said only, 'A joke. What I am speaking of could not be less like love. It is as constant as the stars in their places, a physical force.'

'The sufis say that love is a force, filling everything, impelling everything.'

'The sufis,' Khalid said scornfully. 'Those are the last people on Earth I would consult if I wanted to know how the world works. They moon about love and drink lots of wine and spin themselves. Bah! Islam was an intellectual discipline before the sufis came along, studying the world as it is, we had Ibn Sina and Ibn Rashd and Ibn Khaldun and all the rest, and then the sufis appeared and there hasn't been a single Muslim philosopher or scholar since then who has advanced our understanding of things by a single whit.'

'They have too,' Bahram said. 'They've made it clear how important love is in the world.'

'Love, oh yes, all is love, God is love, but if everything is love and all is one with Allah, then why do they have to get so drunk every day?'

Iwang laughed. Bahram said, 'They don't really, you know.'

'They do! And the good fellowship halls fill up with good fellows looking for a good time, and the madressas grow emptier, and the khans give them less, and here we are in the year 1020 arguing over the ideas of the ancient Frengis, without a single idea why things act the way they do. We know nothing! Nothing!'

'We have to start small,' Iwang said.

'We can't start small! Everything is all tied together!'

'Well, then we need to isolate one set of actions that we can see and control, and then study that, and see if we can understand it. Then work onwards from there. Something like this falling, just the simplest movement. If we understood movement, we could study its manifestations in other things.'

Khalid thought about that. He had finally stopped dropping things through the device.

'Come here with me,' Iwang said. 'Let me show you something that makes me curious.'

They followed him towards the shop containing the big furnaces. 'See how you obtain such hot fires now. Your waterworks drive the bellows faster than any number of puffers ever could, and the heat of the fire is accordingly higher. Now, Aristotle says fire is trapped in wood, and released by heat. Fair enough, but why does more air inake the fire burn hotter? Why does wind drive a wildfire so? Does it mean air is essential to fire? Could we find out? If we built a chamber in which the air was pulled out by the bellows rather than pushed in, would the fire burn less?'

'Suck air out of a chamber?' Khalid said.

'Yes. Arrange a valve that lets air out but won't let it back in. Pump out what's there, and then hold any replacement air out.'

'Interesting! But what would remain in the chamber then?'

Iwang shrugged. 'I don't know. A void? A piece of the original void, perhaps? Ask the lamas about that, or your sufis. Or Aristotle. Or just make a glass chamber, and look in it.'

' I will,' Khalid said.