Doing away with a physical hull – or treating the exterior of every component as a hull, depending on how you looked at it – had been no great leap for GSVs. Ships thought of their multiple-layer field-complex enclosures as their true hulls anyway. That was where all the important stuff happened in relation to the outside: that was where the sensory fields were, where any stray impacts were absorbed, where concentric layers of shielding tuned to various parts of the electro-magnetic spectrum lurked, where holes could be opened to allow smaller units, modules and ships to enter and depart, and – especially in the case of the larger vessels – where atmospheric pressure was kept in, and sun-lines could be formed and controlled to provide light for any parkland carried on the top of the ship’s solid hull.

Frankly the material bit inside was just there to provide a sort of neat wrapping for all the truly internal bits and pieces like accommodation and social spaces.

Comfortably over two hundred kilometres long even by the most conservative of measurement regimes, fabulously, ellipsoidally rotund, dazzling with multiple sun-lines and tiny artificial stars providing illumination for motley steps and levels and layers of riotous vegetation – belonging, strictly speaking, on thousands of different worlds spread across the galaxy – boasting hundreds of contrasting landscapes from the most mathematically manicured to the most (seemingly) pristinely, savagely wild, all contained on slab-storeys of components generally kilometres high, each stratified within one of a dozen stacked atmospheric gradients, the ship’s cosseted internals were riddled, woven and saturated with domesticated, tamed and semi-wild life in hundreds of thousands of smaller enclosed habitats, while its buzzing, external, bewilderingly complex archi-geographic lines were made fuzzy, imprecisely seen by near-uncountable numbers of craft moving within that vast, elongated bubble of air – from smaller classes of GSV through other ships, modules, shuttles and aircraft all the way down to individual humans in float-harnesses, single drones and even smaller machines, as well as thousands of species of winged and lighter-than-air bio-creatures – the Empiricist was, in sum, home to hundreds of billions of animals and over thirteen billion humans and drones.

The people of the Culture, better than ninety-five per cent of them housed across the vast, distributed bucolic hinterland of the Orbitals, scattered throughout the civilised galaxy like a million glowing bracelets, were used to thinking of the GSVs as being their true mega-cities – albeit determinedly highly mobile, high-speed mega-cities – but GSVs like the Empiricist were on another level and of another order entirely; they held the populations of worlds, of entire inhabited stellar systems. Zyse, the Gzilt home planet and the giant GSV’s destination, held over three billion people. The whole of the Gzilt system added another twenty billion, in part-habiformed worlds and moons, microrbitals and other habitats. The Empiricist arriving was like another half a solar system of people being added, like another four mature, substantial planets’ worth of souls suddenly coming to visit.