Exodus: The Archimedes Engine, and a different take on mind uploading

I recently finished reading Peter F. Hamilton’s book: Exodus: The Archimedes Engine. It takes place in a far future where humanity has fled the solar system in relativistic ark ships, looking for new homes. One group of arks discover a bounty of habitable worlds in the Centauri Cluster about 16,000 light years from Earth. Someone named Asteria sends out a “Green Worlds” signal to all the other arks out there.

There’s no FTL in this universe, so the early settlers in the cluster then have over twenty thousand years of history before the other arks begin arriving. The early settlers spread throughout the cluster, and through genetic engineering take on a range of transhuman forms and philosophies. Collectively these species are known as Celestials. They also breed a number of other species for various subservient roles, which are collectively known as Changelings.

There are titanic wars during the early millenia, known as the Remnant Era. This leads to a large number of ruined worlds, many of which continue to harbor ancient ruins and the remnants of advanced weaponry. After the Remnant Era, a particularly powerful group of Celestials known as the Elohim construct a network between all the stars in the cluster, known as the Gates of Heaven. The gates do not allow FTL travel, but they do rapidly accelerate craft to 99.9% of lightspeed, with another gate at the destination rapidly decelerating that craft, which facilitates relativistic travel around the cluster.

By the time they do start arriving, the humans on the other arks are seen as inferior throwbacks. Most Celestials want nothing to do with them. Many of these later groups are forced to settle on Remnant worlds, although one matriarchal society, known as the Crown Dominion, allows them to settle on a couple of planets in their capital system. But the Crown Dominion sees the humans as little more than an economic asset. By the standards of human history, their standard of living is high, but they are not allowed access to Celestial technologies, at least other than whatever Remnant artifacts they can find.

The Crown Dominion Celestials are interesting. They are somewhat human shaped, but much taller and thinner. They’re immortal, but that immortality comes about through maintaining a mindline.

Their children, called “spawn”, reach physical maturity rapidly. Parents have the ability to share skills and memories with their spawn, called “gifts” in the story. Eventually the parent, when near death, or just tired of their current body, chooses one of their spawn, and transfers all their remaining skills and memory into that body, essentially making it their new body. However, they can only do this before the child reaches about fifteen years old. After that, their mind becomes resistant to taking on a different persona. They then become a “new life”, basically the start of a new mindline.

A human from one of the arks asks why they don’t just grow clone bodies and download their minds into the clone. The reply is that that would require a technological civilization. The mindline transfer is entirely biological, happening through nerve connections when bodies are physically touching each other, the result of genetic engineering, and so purportedly could be maintained even if the Crown Dominion civilization were to be thrown back into the stone ages.

However, to ensure their mindline is preserved, everyone constantly maintains an inventory of young spawn, and keeps at least one close by in case of an accident. And it makes the Crown Dominion value social stability above all else. The result is a static society which is becoming stagnant. This mindline related stagnation is observed in the novel by at least one member of another Celestial species, indicating that the mindline is not a universal trait among the Celestials. (The book doesn’t reveal whether the other Celestials are immortal though other means or have just decided to be mortal.)

The mechanism also has a vulnerability, one that becomes apparent in the book.

Hamilton does seem to push this idea a bit into implausible territory when, at one point in the story, a dying Celestial is able to implant a limited version of himself into the brain of a regular human. I can see sharing skills and memories between brains genetically engineered for it. But we know enough about natural brains to know that information can’t simply be transferred into them, at least not rapidly.

Still, it’s an interesting take on the idea of immortality through mind copying. In some ways it reminds me of the method used in the Avatar movies. It seems to nicely step around concerns about whether consciousness could exist in a different substrate, albeit with a biological framework one human character considers “hellish weird”.

At the beginning of the novel, the year is 42,350 AD. The main protagonist, Finn, comes from a relatively privileged aristocratic background, but yearns for the freedom to travel. Somewhat naive, he wants to become a Traveler, a class of humans who travel around the cluster, exploring and finding Remnant artifacts, as well as making other trade deals.

He finds his opportunity when he meets Ellie and Josias Apone. Josias is the owner of an ark which has just arrived. However, as Finn tries to capitalize on that opportunity, he finds himself drawn into a political plot, which takes place against the backdrop of ever rising tensions between the humans and Celestials, and the return of an ancient enemy.

There’s a lot going on in this long book. (Hamilton is known for putting out thousand page doorstoppers; this one is 904 pages.) I thoroughly enjoyed it. It captured me in a way few books do anymore. It’s the first in a series, so be warned that it does end on a cliffhanger. It also takes place in a setting used for a game that Hamilton helped design the world for, although he stresses in interviews that he had complete freedom on the story.

I’ve tried a few of Hamilton’s earlier novels over the decades, but found his long descriptions off putting, and so had largely written off his books, even though their descriptions are enticing. But the description of this book was too good to ignore. I have a weakness for posthuman space opera without FTL. I was steeled for a slog, but was pleasantly surprised to discover that his writing seems to have tightened considerably. He still tends to go into more detailed descriptions than I care for, but it’s well within my tolerance now. Which is leading me to take another look at his more recent work.

Anyway, if epic space opera is your cup of tea, you’ll want to check this one out.

Have you read it? If so what did what you think? I’d welcome any recommendations for similar stories.