'All right, Father, maybe so, but don't burn the books! There may be something useful in some of them, you need to make distinctions. And besides, they were expensive.'

Khalid only snarled and made the sound of spitting.

Bahram told Iwang about this incident the next time he was in town. 'He burned a lot of books. I couldn't talk him out of it. I try to get him to see the love filling everything, but he doesn't see it.'

The big Tibetan blew air through his lips like a camel. 'That approach will never work with Khalid,' he said. 'It's easy for you to be full of love, being young and whole. Khalid is old and one handed. He is out of balance, yin and yang are disarranged. Love has nothing to do with it.' Iwang was no sufi.

Bahram sighed. 'Well, I don't know what to do then. You need to help me, Iwang. He's going to burn all his books and destroy all his apparatus, and then who knows what will happen to him.'

Iwang grumbled something inaudible.

'what?'

'I'll think it over. Give me some time.'

'There isn't much time. He'll break all the apparatus next.'

Aristotle was Wrong

The very next day Khalid ordered the blacksmith apprentices to move everything in the alchemical shops out into the yard to be destroyed. He had a black and wild look as he watched it all shed dust in the sunlight. Sand baths, water baths, descensory furnaces, stills, cucurbits, flasks, alumbixes, alembics with double or even triple spouts; all stood in a haze of antique dust. The largest battery alembic had last been used for distilling rose water, and seeing it Khalid snorted. 'That's the only thing we could make work. All this stuff, and we made rose water.'

Mortars and pestles, phials, flasks, basins and beakers, glass crystallizing dishes, jugs, casseroles, candle lamps, naphtha lamps, braziers, spatulas, tongs, ladles, shears, hammers, aludels, funnels, miscellaneous lenses, filters of hair, cloth and linen: finally everything was out in the sun. Khalid waved it all away. 'Burn it all, or if it won't burn, break it up and throw it in the river.'

But just then Iwang arrived, carrying a small glass and silver mechanism. He frowned when he saw the display. 'Some of this you could at least sell,' he said to Khalid. 'Don't you still have debts?'

'I don't care,' Khalid said. 'I won't sell lies.'

'It's not the apparatus that lies,' Iwang said. 'Some of this stuff could prove very useful.'

Khalid glared at him blackly. Iwang decided to change the subject, and raised his device to Khalid's attention. 'I brought you a toy that refutes all Aristotle.'

Surprised, Khalid examined the thing. Two iron balls sat in an arna ture that looked to Bahram like one of the waterwheel triphammers in miniature.

'Water poured here will weight the rocker, here, and the two doors are one, and open at the same time. One side can't open before the other, see?'

'Of course.'

'Yes, obvious, but consider, Aristotle says that a heavier mass will fall faster than a lighter mass, because it has more of the predilection to join the Earth. But look. Here are the two iron balls, one big and one small, heavy and light. Place them on the doors, set the device level, using a bubble level, high on your outside wall, where there is a good distance to fall. A minaret would be better, the Tower of Death would be better yet, but even from your wall it will work.'

They did as he suggested, Khalid climbing the ladder slowly to inspect the arrangement.

'Now, pour water in the funnel, and watch.'

The water filled the lower basin until the doors suddenly fell open. The two balls fell. They hit the ground at the same time.

'Ho,' Khalid said, and clambered down the ladder to retrieve the balls and try it again, after hefting them, and even weighing them precisely on one of his scales.

'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.'