Diaspora by Greg Egan - a review

Diaspora, Breg Egan - book cover
Diaspora by Greg Egan is probably the most intense science-fiction book I've ever read. Intense in the way it brings highly detailed and technically difficult concepts and theories from the edges (and beyond) of current physics and presents them at length to the reader.

It's no surprise to me to see a large number of reviews for this book are mostly polarised into two camps; namely 'best book ever' and 'what the hell was that about?'

Personally, I lean towards the 'best book ever' camp, but not as forcefully as some! I enjoyed it and that is what matters.

This is a tough book for sure though. Even the opening chapters on the birth of a new digital mind will leave many people grasping around for just what on earth Egan is going on about.

To some, this has become an elitist badge of honour - those 'getting it' becoming reassured in their intellect and looking down on those that fail to see the joy in reading page after page of detail on the various processes and developments that go into creating new digital life.

I wonder how some of those delighting in their own excellence at being able to understand Egan's depth would fair with Mrs Dalloway or The Return of the Native? Perhaps the shoe would be on the other foot...

Anyway, it's not for me to say what people should and shouldn't enjoy and so this 'review' won't try to impress you with pity quotes and overeager attempts at grandiose statement. Instead, I'll just share with you how I managed to actually read this book.

Learning to read difficult books

So here comes the big secret - write stuff down.

Amazing huh? "What incredible insight!" I hear you quip.

Well, try it. Honestly, write down items about the novel as you are going along. Write down places mentioned, characters name and descriptions, objects described, lifeforms, races, machines, concepts and more.

Keep track of it all and come back to it when you see something mentioned and realise you've forgotten the detail of what it was or how it worked.

I've provided my notes on Diaspora below so you can get a sense of what I mean. But the reality is, just keep notes, maybe in Evernote, maybe in a physical notebook, maybe in a plain text file or whatever. The details don't matter as long as it suits you and the way you like to read.

Tracking the plot

The next thing you should do is track the plot of the book. As well as writing down the detail, keeping a brief overview of the plot as is develops means you can come back to your own notes should you go a few weeks between putting the book down and picking it up again.

We're not all blessed with stable routines or time to sit and concentrate on difficult books for pleasure. So tracking the plot in your own words is the key to actually getting through to that all important last page.

How much detail?

As much or as little as you like. And you don't need to be consistent or keep things well formatted or even use whole sentences. Just do what gives you the info you need so that when you need to look back at your notes there's enough detail there to remind you about that particular thing.

Same with the plot, sometimes you'll want to be more detailed as there might be more going on or maybe more intricate detail that you want to remember. Other times there will be no point putting much more than 'they went to X'.

The idea is to keep relevant notes that are easy for you to make and useful for you to refer to, not an essay designed to be used by others.

My notes on Diaspora by Greg Egan

So here are my notes then. I spent a fair while tidying them up to make presentable as I didn't really care what they looked like when using them to help read. After all, they were neat enough for me to understand and that was all that mattered.

Feel free to change the format and make something that works for you, but I can't recommend strongly enough that you write whilst you read.

Try it, it'll change the way you feel about reading!

Author - Greg Egan


    - think 'metropolis'. Computer hardware that hosts the electronic
      'versions' of humans. 

    - somewhere the Diaspora is heading towards.

    - Yatima's polis

    - Hashim's polis. More arty?

    - Surrounded by forest
    - Population of 12,093 but looking to hold 4,000 more within 10 years

Lacerta G1
    - Something big happened
    - Pair of binary neutron stars 100 light lears from earth
    - Decaying orbit in 7 million years will merge
    - Merge = gamma ray burst = bad for earth

    - Heading towards it. Somewhere in space.

    - Situated in Vegan star system
    - Find carpet life thing in ocean. 
    - C-Z polis arrives there carrying copy of Paolo.
    - Lamda shore tsunami every 90 years or so.

Sirius B
    - Robots there.
    - Weird emmisons. Might be dragging white dwarf from orbit to use as

Swift, Voltaire System
    - Innermost planet
    - Unusual  chemistry - none of the most abundant isotopes, only the
      heaviest isotopes of the most common elements
    - Someone had deliberately transmuted the atmosphere to the heaviest
      isotopes to putting it's life. Otherwise the atmosphere would have been
      lost to SPACE long ago.

Lilliput Base
    - Dome on surface of Swift. Used for scientific inquiry. 20 meter diameter.
    - Built using femtomachines invented 100 years before arrival at Swift
    - Preform experiment to find oit if there is uniqueness to Swift neutrons.
      Experiment measures a feature of Kozuch theory that says you can
      concatenate length limited wormholes together 'in' a single Neutron.
      Seems to be a way of encoding data.
    - They find 6 exabytes of encoded something.
    - Data is revealed as 2d images, frames, like a movie, depicting data over
      millions of years. Its a record, a prediction/forecast, of large scale
      energetic events like gamma ray bursts and quazar eruptions.
    - 26000 years ago an event in the Galactic core occured. In a few thousand
      years it'll reach this part of space.


    - not sure.

    - process of creating new digital human from a mind seed and done by the
      conceptory. This involves no parents hence the orphan bit.

Gesalt and Linear perception 
    - the equivalent of seeing and hearing respectively for digital humans.

    - Run by Karpal. Part of it on the moon - Bullialdus.
    - Massive solar system wide gravitational wave detection array made up of
      individual installations

    - some kind of wormhole building accelerator?

Carpet lifeform
    - Single molecule, massive in 2d, folded in on itself from outside to
    - Huge chain of unbroken one layer thick polymer made from polysaccharides.
    - Built into slab several microns thick and made from.about 20000 subunits
      of different molecular shape.
    - Uses UV created free radicals to grow. Traps them at catalyst sites.j
    - Made from Hao Wang tiles, named after mathmatician 
    - Properties of giant computer. Sub units form Turing Machine (original 1d
      tape version)
    - Complexity revealed in Fourier transform of edge which reveals
      a multidimensional frequency space.of over a thousand dimensions
    - Can think of this like a Polis. The carpet is the computational substrate
      upon which 'simulated' but 'real' life exists, just as in a Polis.


Transmuters - 

Transmitters - 

    - statics, dreamers, bridgers etc

    - robotic life with human consciousness


    - genderless. Digital. 
    - Resides and birthed (orphanogenesis) in Konishi polis.
    - Studying maths out of desire to be able to push boundries uniquely, not
      with cloned knowledge of predecessors 

    - icon: fleshless skeleton of twigs and branches, skill carved from knotted
    - Mathematician, teaching Yatima.

    - Concerned with aesthetics. 
    - Studying with Ashton-Laval? 
    - Hisscape contents is constantly 'wriggling', glowing and highly fractal. 
    - Seeing Gabriel from Carter-Zimmerman polis? 
    - Shares parents with blanca?

    - Built forge with Yatima?,Z
    - Blanca lover

    - Gabriel lover

    - artist friend of inoshiro

Orlando Venetti
    - Flesher. Lives in Atlanta.
    - Done augmentation to control plant life in forest.
    - Beard. Green robe with gold lining
    - Becomes member of C-Z Polis after introdus by Yatima just after Lacerta
      gamma ray strike.
    - Travels in diaspora. 

Liana Zabini
    - Female flesher
    - Brown hair, green eyes
    - Neuroembriologist

    - Knows Yatima. Hi

    - Runs TERAGO on the moon. 
    - Gleisner

    - On C-Z polis at Orpheus
    - Bug like creature currently.
    - Scanned in 21st century. Rewritten personality several times. Thinks of
      himself as great great grandson of original.



- Yatima travelling somewhere in space as part of Diaspora with a companion
  traveller. Possibly to Swift. 


Chapter 1

- Goes back in time to Yatima birth. Explains orphanogenesis

Chapter 2

- Yatima studies with Ridiya then studies on vis own in the Truth Mines
  (axiomic learning 'tunnels' branching from prior truths - basically
  representative of how maths is built on proofs/assumptions if simpler axioms)
- Inoshiro arrives and attempts to get Yatima to go to artist thing. 
- Yatima goes to art thing. Takes on the mind altering outlook. Decides nothing
  really changed and can only find truth in the Mines.

Chapter 3

- Yatima clones into a robot (Gleisner) along with Inoshiro. They are in
  a forest.
- They walk through forest. Find something called a replicator which is
  dangerous and destroy it. Something about memes?
- Meet flesher called Orlando Venetti
- Walk through the new city (old is buried in the forest)
- Meet another flesher called Liana Zambini
- They are 'bridgers'. They're artificially altering their population to the
  extemes of diversity in order to regain communication with all of the
  extremely modified 'exuberants' (highly modified humans who have asked
  themselves genetically) in order to prevent complete fragmentation of human
  flesher culture.
- They talk with the inhabitants.
- They leave. Inoshiro gets second thoughts about leaving. Leaves anyway.


- Yatima and Paolo talk about Karpal whilst they are travelling through space
  towards Weyl
- Switches to karpal perspective on moon
- Bullialdus - part oF TERAGO Gravitational Wave Detector.
- Discrepancy in data of Lacarta G1 gravitational decay. Periodically decaying
  too fast.
- Lac suddenly loses 3 minutes from orbit, equivalent to 7000km distance
  closer. No way to explain energy loss.
- Neutron colour neutrality symmetry breaking could lead to meson jets along
  direction of motion of neutron stars orbits. This could slow them to 0, dead
  stop. They then fall together silently with enormous collisional energy. 
- Process takes 4 days.
- Plot switches back to Yatima ine day before collision in vis Homescape trying
  to objectively measure what consciousness is
- Inoshiro arrives and informs news of the impending gamma ray burst. Yatima
  decides they must return to fleshers on earth to earn then add they can
  establish communication any other way.
- They go and meet the fleshers, warn them.
- Big meeting with loads of flesher factions
- Generally the fleshers start to prepare
- Inoshiro reveals ved have used the nanotech to save fleshers against their
- Yatima helps a bit where ve can. Not much happens. Ve goes on a swing but
  doesnt know how to actually make it swing.
- Lacerta continues to speed up
- Yatima joined by child. They swing on the swing
- Gamma ray burst hits. Causes local loghtening storm as radio wave energy
  shorts to ground through the storm clouds. Buildings destroyed all over town.
- Liana found dead.
- They Introdus Orlando who was dying after being crushed by falling ceiling.
  Introdus 12 more when caught by mob and cut up. Link to Polis restored before
  they're gleisher bodies destroyed so they 'survive' and transfer back

Chapter 6 - divergence

- Switches to Konshi polis
- 20 years later. Earth dying. All oxygen producing life dying. 
- In an underground area. Refugees mostly stopped arriving now.
- Looks like there had been an evacuation underway.
- Gleisners already sent out interstellar ships. C-Z polis going to do the same
  but nit physical ones, they're going to try build wormholes.
- Inoshiro not dealt well.with the trauma of the fleshers demise. Ve overwrote
  verself with old fatalist philosophy. Effextively killed ver personality and
  replaced it with new one.
- Yatima to join C-Z polis. Upset at 'death' of inoshiro.

Chapter 7

- Explanation of wormhole physics and theory that replaced GR.
- Ober 3000 designs of wormhole building machines - but Gabriel looked forward
  to the challenge.
- Chapter 8 - 800 or so years later
- testing forge. First success.
-  Long description of building the wormhole and Gabriel/Blanca relationship.
- Problem with Kozuch Theory. Wormhole was as long as true physical distance.
  Theory will need to be updated or even replaced.

Chapter 9 200 yeats later 

- On a diasporic polis travelling to a new system
- Most suspended animation/paused self time. 
- Osvald 'on board'. Seems ship is tiny and scapes just fake larger size. These
  C-Z people experiencing flesher time as disapora progresses, so they
  experience hundreds of uears travel time. 
- Blanco talks to Kozuch recreation avatar and comes upnwith 12 dimension
  alternative to explain long wormhole

Chapter 10 eve of 4th millennium 

Preparation for diaspora

Chapter 11 september 4309 

- Paolo's copy of c-z polis arrives at Orpheus. Finds life. Living carpet
- Vote to send microprobe.
- Send microprobe.
- Probes conduct their work and will send back data via modulated UV
  reflectivity before self destructing.
- Move to 'heart'. Some kind of meeting place that is like being inside an
  organic heart. Minus the blood.
- Talk about Sirus B where robits are.
- Discover Wang Carpets are Turing Machine. They provide computational
  substrate for 'simulation' of life like a Polis. But the life is 'real' just
  like in a Polis.
- With this revelation, C-Z polis cherished belief in primacy of physical world
  is challenged.
- Discovered the squid like creatures inside this computational world
  demonstrate similar characteristics to minds in Polis. Communication via
  touch (the us no corollary of light).
- Squids show an understanding of self through the understanding of others as
  separate minds. And it thinks abouts its own thoughts. It appears conscious.


Chapter 12


- Thinks ves due to arrive shortly at their destination but realises another
  polis must have made a belated discovery as there is still 17 years to go
  until arrival.
- Knows about Orpheus squid.
- Woken because of automated update to ship board astronomy equipment allow
  detection of unusual chemistry on Swift, the innermost planet of the Voltaire
- Realise someone has altered atmosphere to try and prevent it boiling away
- must be to preserve life.

Chapter 13 

Voltaire System, Swift orbit aboard C-Z Polis.  16 March 4953

- Yatima and Orlando view probe data from Swift.
- Lacerta burst had hit this planet too.
- Life remains but not sure to what extent of previous diversity.
- Real question is where are the Transmuters.
- Realise that Neutrons are the key. They are the unique addition to the
- Kozush Theory days Neutrons are wormholes. They have all the degrees of
  freedom need to be unique and not just plain Neutrons as 21st century
  understands them.

Chapter 14 

- They have created Lilliput Base. 20 meter Dome for scientific inquiry. On
  planet surface.
- Meets with Blanca.
- Utterly mind warping rush into a revelation about the universe, its place in
  the 'macrosphere', the Transmuters having synced our entire universe to
  a plank moment in the macro verse, knowledge of potentially how to cross,
  maybe how to communicate with them. 
- Revelation of how Blanca has done much of this theoretical work already.
- Impossible to comprehend all info in one sitting.


Chapter 15 


- Exhibition of macro verse 5+1 dimensions vs our 3+1.
- One key take away is that gravitational potential energy surface is inverted
  leading to no stable orbits. 
- Another revelation; all matter in the macrosphere would collapse or fly
  apart. So no sloar systems. But there would be lots of individual centres of
  mass like stars. Expect to find Transmuters orbiting star (unlikely as have
  to constantly stabalise orbit) or on surface of star.
- Next exhibit talks of how nuclear physics would be altered under this new
  scheme. Electrostatic force becomes linear (complex to understand) and much
  fewer sub atomic particles exist.

Chapter 16

- Inside macrosphere
- Orlando gets to grips with new reality. Alters visual perception to
  accommodate 5 dimensions.
- Find animal and plant life on Poincaré. Evidence of enhancement/alterations.
- Find some kind of mollusc life form. Seems to jave no predators, illness,
  death or otherwise. Possibly Transmuters? Possibly organic Polis of some
- Orlando goes to the surface to explore. He's in a puppet robot mollusc.
  Created to try evoke reaction/communication from the Real Molluscs
- Now call the Molluscs The Hermits
- Orlando goes clone inception and builds a 7 step bridge to communicate with
- Find out Transmuters have moved to another Macrosphere - this time
  4 dimensional.


Chapter 17

- C-Zpolis in Macrosphere
- 46 go to U** (U** is one universe up in the stack)
- Orlando merges with 1st level 5 space clone. 7th level stays on Poincaré.
  Rest kill themselves.

Chapter 18

- C-Z polis U**
- Tjeu get answers from Contingency Handler, non-sentient ambassador sent to
  communicate with new arrivals.
- Find reason for Lacerta - interaction with infinite other universes alters
  multiverse/dimemsional direction of angular momentum of the binary pair. It
  bleeds off as multidimensional spin.
- Reason for core is different -multidimensional spin doesnt interact with
  gravitons, so the energy of the xollapse wont be hidden behind event horizon
  quick enoigh to contain it all. Energy densities will become high enough to
  start creating spacetime, a mini big bang. The energy released before.falling
  behind the event horizon will release enough energy to break up nuclei within
  50,000 light year radius.


Chapter 19

- C-Z Polis in U**
- Communicate knowledge back through U* and to origin U
- Call the new aliens Star Striders
- 6000 cultures in new Galaxy in U**
- Some old as Star Striders.
- 12 from Milky Way.
- Yatima/Paolo decides to follow the Transmuters.

Chapter 20

- Yatima-Venetti Polis U*
- They go from universe to universe following the trail of the Transmuters.
- Find structures. Possibly Polis, hold data, cant decipher it.
- The press on for trillions of levels.
- Turns out structures were Polis. Transmuters were exploring all they could
  become and be.
- Changing shape of Polis summed together to create 5 dimensional ancestral
  image of them.
- They find a level where there is no more structure. Transmuters didn't
  come.tjis far, they stopped ome level back.
- Paolo decides the search is over for him. He will die.
- Over 90 billion years of U time have passed.
- Yatima goes on but returns to first exploring Truth Mines. 
- Ends with ver returning to learning the axioms of maths - this time with no

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