Excession

The Excession of the title is a perfect black-body sphere that appears mysteriously on the edge of Culture space, appearing to be older than the Universe itself and that resists the attempts of the Culture and technologically equivalent societies (notably the Zetetic Elench) to probe it. The Interesting Times Gang (ITG), an informal group of Minds loosely connected with Special Circumstances, try to manage the Culture's response to the Excession. The Affront, a rapidly expanding race which practises systematic sadism towards subject species and its own females and junior males, also try to exploit the Excession by infiltrating a store of mothballed Culture warships and using them to claim control of the mysterious object.

The Sleeper Service, an Eccentric General Systems Vehicle (GSV) who had nominally left the Culture, is instructed to head to the location of the Excession by the ITG. As a condition the Sleeper Service demands that Genar-Hofoen, a human member of Contact, attend it to seek a resolution with his ex-lover, Dajeil, who lives in solitude on the GSV. They had had an intense love-affair and, after a series of sex changes, had each become impregnated by the other until Genar-Hofoen was unfaithful and Dajeil attacked Genar-Hofoen, killing the unborn child. Dajeil then suspended her pregnancy and withdrew from society for 40 years and the Sleeper Service hopes to effect a reconciliation between them.

As the stolen Affront fleet approaches the Excession, the Sleeper Service deploys a fleet of 80,000 remote controlled warships, in a misguided attempt to neutralize the threat. It transpires that the Affront have been manipulated into their grab for power by members of the ITG who thought it was morally imperative to curb the Affront's cruelty by any means, and intend to use the Affront's theft of Culture warships as an excuse for war. The Excession releases a wave of destructive energy towards the Sleeper Service. In desperation, the Sleeper Service transmits a complete copy of its personality, its "Mindstate", into the Excession, which has the effect of halting the attack. The Excession then vanishes as mysteriously as it appeared and the brief war with the Affront is halted.

During these events, and after speaking with Genar-Hofoen, Dajeil decides to complete her pregnancy and remain on the Sleeper Service, which sets course for a satellite galaxy. Genar-Hofoen returns to the Affront, having been rewarded by being physically transformed into a member of the Affront species (whose company he finds more stimulating than that of the Culture's people).

The book's epilogue reveals that the Excession is a sentient entity that was acting as a bridge for a procession of beings that travel between universes. It also assesses whether the species and societies it encounters are suitable to be enlightened about some unknown further existence beyond the universe; as a result of events in the story the Excession concludes that the civilisations it has encountered in this universe are not yet ready. It also takes the name given to it by the Culture – The Excession – as its own – in an oblique reference to the aforementioned Affront species, who had been named by another species in an attempt to label them as a lost cause of hyper-sadistic freaks.

This novel is about how the Culture deals with an Outside Context Problem (OCP), the kind of problem "most civilizations would encounter just once, and which they tended to encounter rather in the same way a sentence encountered a full stop."

This is a problem that is "outside the context" as it is generally not considered until it occurs, and the capacity to actually conceive of or consider the OCP in the first place may not be possible or very limited (i.e., the majority of the group's population may not have the knowledge or ability to realize that the OCP can arise, or assume it is extremely unlikely). An example of OCP is an event in which a civilization does not consider the possibility that a much more technologically advanced society can exist, and then encounters one. The term is coined by Banks for the purpose of this novel, and described as follows:

An Outside Context Problem was the sort of thing most civilizations encountered just once, and which they tended to encounter rather in the same way a sentence encountered a full stop. The usual example given to illustrate an Outside Context Problem was imagining you were a tribe on a largish, fertile island; you'd tamed the land, invented the wheel or writing or whatever, the neighbors were cooperative or enslaved but at any rate peaceful and you were busy raising temples to yourself with all the excess productive capacity you had, you were in a position of near-absolute power and control which your hallowed ancestors could hardly have dreamed of and the whole situation was just running along nicely like a canoe on wet grass... when suddenly this bristling lump of iron appears sailless and trailing steam in the bay and these guys carrying long funny-looking sticks come ashore and announce you've just been discovered, you're all subjects of the Emperor now, he's keen on presents called tax and these bright-eyed holy men would like a word with your priests.

Banks has noted that he spent much time playing the Civilization computer game (appearing to refer to the first version of the game series) before writing the book and that it was one of the inspirations for the concept of the 'Outside Context Problem' central to the novel. In an interview, Banks specifically compares this to having a Civilization battleship arrive while the player is still using wooden sailing ships.[1][2]

• Links to reviews of Banks' works, including Excession Archived 2 January 2020 at the Wayback Machine