It's been said that to us an alien of sufficient power and complexity would be indistinguishable from a god. It's also been said that if we had enough knowledge we would be able to prove, one way or another, the truth of religion. However, if we could do that its character would change completely. It would no longer involve faith and belief, it would simply be another branch of science, the gods other beings who could be studied and communicated with, heaven and hell realms of exploration and even conquest.
I'm not sure what Iain Banks' religious views are. From his novels I would be surprised if he was not an atheist, or at least an agnostic. Yet he has arguably the most fertile imagination of any living speculative fiction writer and he is certainly more than capable of imagining heaven, hell and all manner of gods or demons to inhabit them.Many of his science fiction novels are set in a Galactic-scale civilisation known as the Culture, a kind of extreme libertarian society in which the problem of scarcity has been solved, virtually nothing is technically impossible, and the range of living creatures is huge and bewildering. Yet after he has spent time exploring the emotional and dramatic possibilities of this kind of power and diversity he is left at the doorstep of the eternal, and blunders on where angels fear to tread. After all, angels themselves may be just another species in a vast, surprising galaxy.
His previous Culture novel, Surface Detail, dealt with the question of hell - or to be more precise, hells. Many civilisations, it seems, view the existence of hell as useful or even essential. Hence, they maintain virtual realms of torment to which they can send the consciousnesses of their malefactors. The realms are virtual but the torments are real and extreme.
Various galactic campaigners, however, see hells as cruel and abusive and are campaigning for treaty in which they will be abolished. Not content with the slow and inconclusive process of galactic diplomacy, some activists go further, invading selected hells and attempting to subvert them and expose abuses of the practice.
One of these campaigners is caught in the hell he is trying to infiltrate, and as punishment for his crime is transformed into a kind of gryphon, able to release one soul from torment each day. Each kill adds one more ache to his own body so that he literally takes their sufferings on himself - but the rules do not allow him to save everyone, and he must choose more or less at random. Does this remind you, in an odd kind of way, of any real life religion you might have come across?
Not surprisingly, we eventually discover that most of these virtual hells are hosted in a mid-scale planetary civilisation ruled by a corrupt, ruthless dictator. His fate and those of the hells he hosts are tightly bound together.
Of course after dealing with hell Banks' latest Culture story, The Hydrogen Sonata, deals with heaven, or perhaps more accurately with something akin to Nirvana. In his galaxy this is referred to as "subliming". Individuals can sublime if they choose, particularly powerful and complex ones, but the most effective way of subliming is for a whole society to do it together. If they do so, beings of some sort will come for them and take them to an alternative realm, some kind of multi-dimensional universe which is so far beyond the understanding of people within the "normal" galaxy that even those rare individuals who return are unable to communicate anything meaningful about it.
Attaining the Sublime, like being sent to hell, is not a matter of virtue or spiritual discipline. Just as you can be sent to hell on the whim of a corrupt dictator, the story of the subliming of the Gzilt around which The Hydrogen Sonata centres shows that the path can be laid through political manipulation, lies and even murder. Nor does the Gzilt's decision to Sublime lead to them becoming more holy - as the time approaches their polity descends into chaos.
"Gods" appear in a number of Culture novels as well and this one has two sorts. The first, the Zihdren, appear as angelic creatures in the "Book of Truth", the primitive religion of the Gzilt. Unlike other similar religions, the Book of Truth has survived into the era of space travel because it makes remarkable predictions, the full import of which only become apparent as technology advances. This is because the Gzilt have been victims of a kind of cosmic experiment perpetrated by the Zihdren, who planted them with a set of scientific information disguised as a religious text to see what would happen. Hence, the galaxy's best candidate for a true religion is in fact a hoax and the creatures who stand in for gods are mere practical jokers.
And then of course there are the perpetual gods of the Culture, the Minds, unfathomably powerful and complex artificial intelligences which are its effective rulers and guardians. These are the aliens so powerful they appear to be gods. They are, paradoxically, originally the products of biological/humanoid invention, although they have long since outstripped their inventors and taken on a life of their own.
Fortunately for the galaxy, unlike the rogue AIs of the Terminator movies or Battlestar Galactica the Minds are essentially benign, committed in the main to preserving and respecting life rather than destroying it. Yet as the Culture novels have progressed, the Minds have grown more distant from the humans they protect and serve, or rule and partronise, or whatever.
In The Hydrogen Sonata we meet the galaxy's oldest living person, a man called QiRia who has been continuously alive for over 9,000 years. Here's what he has to say about the Minds.
They are as gods of old were merely imagined to be; we are mud in their hands, flies to be toyed with. Etc., blah. They are rarely malicious, never vicious; not to us. Mainly this is because we are so far below them it would be demeaning to get that worked up about us and our feelings, but the thing is, they are vastly powerful artefacts, with senses and abilities and strengths that we only fool ourselves we know about or understand, and the subtlest, most infinitesimal of their machinations can bruise us, crush us utterly, if it catches us wrong.
So here are Banks' gods. Cruel tyrants who can send you to virtual eternal torment if you do wrong, or if they just dislike you. Practical jokers, playing tricks and conducting experiments on helpless beings, the truest religion ultimately being the most patently false. Our own artefacts, gotten out of hand and grown so far beyond us that they have agendas we can never understand. Yet despite his cynicism he leaves us mysteries to explore, realms beyond our understanding, and the possibility that we can become something infinitely more than we are now.