Cixin Liu’s sci-fi trilogy is not comforting nor uplifting. The feeling I got from his Three Body Problem trilogy is the same as how I felt after reading Stephen Baxter’s earlier stories (before he turned his attention to alternate history and near-future cli-fi.) It’s not a bad thing. Simply, it is a bracing experience.

First of all, I loved Liu’s trilogy; there is something different to like about each book. The tone of the Three-Body Problem differed so much from The Dark Forest and Death’s End. In Three-Body problem, it was pleasant to read about a female vantage point, but one whose personality was shaped by the Chinese Cultural Revolution. The Dark Forest changed tone completely; once news of an impending invasion, it became a psychological thriller. How do humans deal with not only the end of science, but what it means to have a ceiling imposed on the technological heights one can achieve. It turned game theory and the derivation of the mathematics of alien contact into an exciting novel. That is a testament to the talent and work of Liu and his interpreter.  Death’s End changed tone yet again, and I suspect the most “western” in outlook. Comparisons are made between the Madonna and the heroine, time and again. In each instance, she was forced to make hard decisions, and in case, she chose a path that reaffirms a liberal humanist faith in the world. As Liu makes clear, it is likely the wrong choice, but it is one he sympathizes with, in the end. The blow is softened with a reasonably optimistic ending.

The centerpiece of this series is in the extrapolation of the technologies that humans create. At the end of The Dark Forest, detente is reached. The  alien race, Trisolarans,released the barriers to technological progress. The beginning of Death’s End, however, shows that this is but a ceasefire. The aliens had already sent another colonising wave. The threat remains.

What I want to most focus on is a fairly quiet moment. Prior to introducing various Deux ex machina to save the human race, there is a point in the novel when it is clear that Earth is lost. Humanity met the Trisolarans with a nascent starfleet, only to see it nearly destroyed. A few ships were able to escape. The fascinating point is in how Liu describes their response.

Each crew concludes that, given that there is no Earth to return to, they focus on the ships in near proximity. Resources are now finite. Entropy reigns and will grind down the sturdiest of spaceships. How to best ensure survival of one’s ship? Simply, by maximizing resources while minimizing use. And since there are other ships in the vicinity, with each ship being, presumably, resources relative to the others… But that is not where the novel ends.

The second novel ended when humans found out that the universe is red in tooth and claw. This is the meaning of the Dark Forest. Every civilization is a hunter and prey. Obscurity is the only defense. Once exposed, it is a matter of time before other hunters see the prey. And why do we see the universe as hunter prey, rather than as a Galactic Empire? Light speed, and time dilation. The speed of light limits communication. Even a “short” distance of several light years mean that information exchange takes place in the decades. Time dilation occurs during travel between the stars. While one can asymptotically reach light speed – and the crew experiences a reasonably short time span, the rest of the universe speeds by. The travelers’ technology remain static, while both the home and target worlds continue apace. By the time one arrives as the destination, they may be in for an unpleasant surprise as the inferior target civilization has surpassed technology of the invaders.

In this context, it seems easier to just shoot first.

That’s what it means to be in the Dark Forest. Communication takes too long; time dilation puts the traveler at a disadvantage. Assume exponential increase in technology base.

The way Liu constructed first contact is that the escaping spaceships are essentially separate civilizations. Each ship assumed that earth will be destroyed. Each ship is then the “flagship” of humanity. Coupled with finite resources, it is clear what they must do what they can to secure survival.

I thought the insight that surprised me most is that when a spaceship is cut off from humanity, it will become something different. The calculus is fundamentally changed when there is no home, no resources, no “future” back home.

I can’t say the rest of the novel held surprises, if one simply amps up one’s cynicism.

The humans were able to reach detente by threatening exposure of the location of the Trisolarans’ home system. Based on the nature of transmissions and the signatures of space-faring lifeforms, it is conceivable that other lifeforms will work out other systems that Trisolarans have an interest in, including Earth. By exposing one system, Earthers basically engaged in scorched Earth policy, rendering the planet undesirable. So the cold war idea of mutually assured destruction is resurrected and writ as universal law. For their own reasons, Trisolarans would prefer to colonise somewhere else, since there is a higher likelihood of destruction. From the Earth’s perspective, they could benefit. They traded in immediate domination for a threat in the indeterminate future.

Cixin Liu’s comments on herd psychology fits into a cynical world view. The MAD system depends on decision speed (no chain of authorization and relies on a set of “algorithms” in responding to a threat). Ruling out the committee, the decision to broadcast spatial coordinates fell to one man. One weakness is in the need to change the guard. How does one choose who we empower to destroy us all? What is interesting is that it is important the person in question is perceived, or analyzed, to be someone who will press the MAD button. The problem isn’t in the person, but the process by which one might decide who should be vested to make that decision. There is no guarantee that the right person will always be selected.

The author chooses to end on a fairly human focused view. Unlike Stephen Baxter, who in a similar circumstance chose to focus on how life, any kind of life, might create their future. But in both cases, it is a sobering display, as the goal is to survive until the heat death of the universe and to outlast all other lifeforms. To paraphrase Tolstoy, there are an infinity of ways to fail and very few to succeed.