Review of Probability Sun by

Book cover for Probability Sun

One day I hope to read a Nancy Kress novel full of amazing, deep, complex characters who manage to transcend the stereotypes often demanded by plot and story. Alas, that day has not yet come.

Probability Moon ended on a bittersweet note. The Zeus and its crew was destroyed when Orbital Object #7 exploded rather than go through the space tunnel. The anthropological team left on World was rescued—just in time, from their perspective, because the Worlders had declared them “unreal” and therefore condemned to death. But in the end, the people of World rescind this label when it becomes clear that one of the expedition members, David Allen, died to warn the Worlders about deadly radiation from the sky. So when humans return to World in Probability Sun, they find they are not unreal, as they first feared, but extremely welcome.

So naturally, they decide to rape the planet.

As we discovered in the previous book, there is another artifact on World, a smaller sphere of similar construction to Orbital Object #7 buried in the Neury Mountains. This expedition’s priority is to study the object and, if it might prove useful, extract it and return it to the Sol system. Of course, after stealing a moon in the last book, perhaps liberating a 25-metre sphere is small change in comparison—indeed, the leader of the expedition, Lyle Kaufman, calls it “ridiculously easy”. However, whereas the theft and subsequent destruction of Orbital Object #7 was wrong, it did not seem to damage World or its inhabitants in any tangible way. As the Ann discovers, the same can’t be said if humanity steals this second device: it will destroy the Worlders’ conception of shared reality, and with it, civlization As World Knows It. If you thought humans were the bad guys in Probability Moon, watch out, because we are all kinds of bastards in Probability Sun.

The culture clash between humans and the people of World, as well as the mechanism of shared reality itself, is much less central to Probability Sun. I don’t miss it; as interesting as shared reality was, Kress explored it fully in the first book, and I think she made the right decision to treat it as backstory and focus on new developments. Instead we get to learn more about the Fallers, with whom humans are at all-out war for our existence. The human military manages to capture a Faller alive—no small feat, for Fallers never allow themselves or their ships to be taken prisoner—and deliver it to Kaufman’s team. Kaufman assigns Marbet Grant to open communication with the Faller. Marbet is a Sensitive, someone with an increased level of empathy and awareness for body language. This makes her a “freak” in the eyes of her contemporary society, so it is a talent she strives to keep hidden. This ostracism is reminiscient of the treatment of the Sleepless in Kress’ series of the same name; it also reminds me of Arlen’s children, from her Hugo-nominated novella Act One.

Marbet slowly develops a rapport with the Faller captive, eventually teaching it the rudiments of sign language. Before she can progress much further, matters go awry and she ends up arrested for treason, although later in the novel we do learn a little more about the Fallers’ knowledge of the artifact Kaufman and his team are studying. Although there is much that could be said about the moral dilemmas Kress poses when it comes to the treatment of the Faller prisoner, to the extraction of the artifact from World, etc., what I really enjoy about this subplot is learning more about the Fallers themselves. The war is part of this trilogy’s backstory, but in Probability Moon the Fallers are essentially a faceless enemy. Now I know more about them (although it’s disappointing that we might be heading toward a climactic genocide dilemma) (TVTropes).

The final main character is civilian physicist Tom Capelo. Unlike the military physicist of Probability Moon, Tom is neither reasonable nor level-headed; in fact, he is a jerk (except to his two daughters). He is the typical “brilliant yet eccentric” scientist du jour, the only one who has a hope in hell of uncovering the physics behind these artifacts. And, of course, his wife was killed by a Faller attack on a civilian colony, so you can guess what happens he finds out Kaufman has been keeping a Faller around on the ship….

I know Kress is striving for Big Moral Dilemmas in this book. There’s the tension between Kaufman and Marbet over the treatment of the Faller, who might be the source of valuable intelligence to the war effort. There’s tension between Kaufman and Tom over whether Tom can figure out how the artifact works and maybe even duplicate it. And there’s the tension between Kaufman and Ann when it comes to the latter’s refusal to endorse the destruction of World’s civilization. Amidst all this, we learn that Lyle Kaufman is not a bad guy, that he hates making these decisions and carrying them out, but that he believes this is genuinely the only way to win the war.

I also know I have harped quite a bit on my dissatisfaction with Kress’ characters in other books, from my experience with the Sleepless trilogy all the way to Probability Moon. Actually, Nancy Kress is beginning to remind me a lot of Robert J. Sawyer: excellent use of plausible physics and technology, but really weak characterization. Nevertheless, I can’t stop reading either of them, because they still write great stories with fascinating themes about society-changing advances in science and technology.

I’m an avid science/technology geek, of course, so Probability Sun’s focus on the physics behind these artifacts is right up my alley. In jumping into our future, Kress has chosen to endorse string theory as the theory-of-everything candidate that wins out in the end, unifying our understanding of quantum mechanics with relativity. Even armed with this knowledge, however, we still don’t know how the alien space tunnels can do what they do—a convenient way for Kress to insert them into her story without having to make the science behind them plausible.

The focus of the science in this book isn’t the physics behind the space tunnels but rather that of their cousin artifacts, the probability weapons that affect whether an atom is going to decay and emit radiation. The scientific speculation gets really heavy in this book, especially compared to Probability Moon. I am able to follow along just, enough to recognize the nods to existing theories—Kress mentions “Calabi-Yau spaces”, which are real things. You’d have to consult a real physicist (or student of physics) to point out where Kress starts to stretch the fabric of the theories (to my knowledge, no one has yet hypothesized the existence of a probability-carrying boson, or “probon” yet), but it’s clear that Kress has done her research and striven for a balance between plausible physics and interesting science fiction. Sometimes the dialogue and exposition is a little heavy—it could have stood being broken up into smaller chunks—but in general I think she gets it right.

Although the colonial dilemma on World and the moral dilemma regarding the Fallers are important parts of Probability Sun, the scientific and philosophical results of Kress’ look at the role of probability in physics is the centrepiece of this story. Always with the human interest angle, Kress reminds us that consciousness is a quantum phenomenon, that the release of neurotransmitters in the brain takes place on a small enough scale that quantum effects become important. And at the quantum level, probability—or more specifically, the probability amplitude—dominates. Quantum effects are indeterministic and uncertain, and hence we express them as probabilities. But what conveys those probabilities? Is there some kind of messenger particle, much as photons convey the electromagnetic force, for “probability” force? (Or is our conception of “probability” entirely model-dependent?)

These are big questions and big ideas, and yeah, it makes me head hurt. But I have to give Kress kudos for managing to wrap them in an entertaining story about humanity exploring space and defending itself against an implacable threat. Probability Sun is no less and no more interesting than Probability Moon; the books are remarkably similar, and I expect much the same from Probability Space. But they are definitely “the good stuff” if you are a science lover like me.


Share on the socials

Tweet Facebook

Let me know what you think

Like/comment on Goodreads

Tweet Email

Enjoying my reviews?

Tip meBuy me a tea