A picture of a Kindle with the book cover of 'Schild's Ladder' on display.
Schild’s Ladder by Greg Egan (Photo by me)

Rating: ๐ŸŒ•๐ŸŒ•๐ŸŒ•๐ŸŒ–๐ŸŒ‘

There’s Hard Science Fiction, and then there’s Greg Egan Hard. I had never heard of the honorable Mr Egan before a friend spoke to me of him many oscillations ago, some time in late 2018. This friend I here mention had never failed me with book recommendations (science fiction ones in particular), and so I, with some hesitation, took the plunge.

This is what I mean by Greg Egan Hard:

“Now imagine a new set of vectors that consist of equal amounts of all these dynamic-law vectors, and that are all orthogonal to each other. These vectors represent definite values of a variable that’s complementary to the law vectors. Branco calls them law-momenta–which is a bit sloppy, because they’re not true Lagrangian conjugates, but never mind."


The amounts of the original vectors you combined were just a series of complex numbers that moved around a circle in the complex plane; to get different vectors, all orthogonal to each other, you just moved around the circle at different rates.

Mr Greg is, as you can see, a serious man. I have to mention that I read 20% of this book back in 2018, and only read the rest of it in December of 2020. Evidently, Schild’s Ladder was too hard for me to climb at the time. I did give up on all forms of reading for over a year, though, so I’m not sure I can blame this book.

It was hard to read. The first 25% aren’t the greatest I’ve come across. I was confused at various parts of the book; either not knowing what was happening, or just being lost in the weird world where this story takes place. I struggled with some of the science; both the real and the imaginary, and I commend Mr Egan over his unique world-building. Between the highly-advanced “classical” (in the physical sense) world, the quirky digital, and the vast, mind-boggling quantum universe, I could almost feel the goo in my brain struggling to keep up.

So, you’ve come this far, and you still have no idea what this book is about. I will pretend this was intentionalโ€”I’m merely giving you an idea of how you’ll feel reading the book. Schild’s Ladder, the book, gets its name from Schild’s ladder, the mathematical concept. The latter ladder is a “first order method for approximating parallel transport of a vector along a curve using only affinely parametrized geodesics”. I understand as much of that as you do.

This story is set 20,000 years into the future, where humans no longer have a need for physical bodies, and are therefore not constrained by space or time. They can travel vast distances as streams of data, and can choose to either live in a body or in the digital realm. Dr Cass, a scientist, stumbles upon a curious theoretical discovery that challenges everything she and her fellow physicists know about the laws of the universe.

In testing these findings, the scientists inadvertently create a novo-vacuum; a new kind of vacuum that expands in all directions at half the speed of light, devouring everything in sight. And that’s where the story begins. How will people deal with a threat they do not understand? Is it a threat at all? And what of the planets, worlds, and cultures that have been or are at risk of being annihilated? Also, how do digital bodies have sex? These are all important questions, each addressed in the book.

While this was a great read for me (I draw plenty of joy out of things I don’t understand), I wouldn’t recommend it to anyone who’s not prepared to be frustrated, bored, annoyed, and puzzled at least a hundred times over. I suppose that makes it both an excellent and a terrible bookโ€”a superposition of sorts. Will you measure it? :)

Quantum tidbits:

โ€œAt the Planck scale, that was no small achievement; a tightrope-walker who managed to circumnavigate the Earth a few billion times before toppling to the ground might be described as having similarly imperfect balance.โ€

โ€œI think everyone lives in at least two time scales: one of them fast and immediate, and too detailed to retain in anything but outline; the other slow enough to be absorbed completely. We think our memory has no gaps, we think we carry our entire past inside us, because weโ€™re accustomed to looking back and seeing only sketches and highlights. But we all experience more than we remember.โ€

โ€œThere’s nothing worse than a label to cement people’s loyalties.โ€

โ€œYou’ll never stop changing, but that doesn’t mean you have to drift in the wind. Every day, you can take the person you’ve been, and the new things you’ve witnessed, and make your own, honest choice as to who you should become. Whatever happens, you can always be true to yourself. But don’t expect to end up with the same inner compass as anyone else. Not unless they started beside you, and climbed beside you every step of the way.โ€

โ€œYou didn’t need gates and barbed wire to make a prison. Familiarity could pin you to the ground, far more efficiently.โ€

โ€œBut when you have a malleable mental structure, intensifying pleasure for its own sake is a very uninteresting cul-de-sac. We worked that out a long time ago.” “Fair enough. But what do you do instead?” Yann sat up and leaned against the side of the bed.โ€ .. [Cut so I don’t spoil this too much ;)]