First, the Trisolaran homeworld was destroyed due to the broadcast from the Gravity. Even if the Trisolarans lack the concept of revenge, later text states that the Trisolarans fear human revenge. So why didn’t the Trisolaran Second Fleet send a few warships to eradicate Earth civilization root and stem? Wouldn’t this also allow the Trisolaran civilization to preserve its strength?
Answer:
90% of questions about The Three-Body Problem can be answered directly by reading the original work. This one belongs to the remaining 10% – it requires combining the original text with some thought to find the answer. Alright, let’s read the original work. After Singer discovers that Trisolaris’s coordinates were cleansed, he initiates a Master core process to trace the source of the mass point that killed that star. This is a task with an almost zero probability of success, but protocol requires it. The process ends quickly, as always, with no result. Think about two questions: Why does protocol require tracing the source of the cleanser? Why is tracing the cleanser’s source often unsuccessful? Simple conclusion: In the cold-shooting zone at the edge of the cosmic battlefield, the truth is: Hide yourself well, and cleanse thoroughly. On one hand, cleanse others; on the other, hide yourself well. Tracing the source of the cleanser is to cleanse the “cleanser” – that’s “cleanse thoroughly”; while hiding yourself well, avoiding being traced by others, even after cleansing a civilization, to prevent being tracked – that’s “hide yourself well.” Ordinary civilizations are both cleansers and hiders. But for lower civilizations, powerless to cleanse, they can only be hiders. Unless they have no choice but to become “singers” (broadcasters), that’s another matter. To reinforce this concept, the author wrote a second paragraph. See the original text: If Singer had the patience to wait, the sincere coordinates would eventually be cleansed by other unknown low-entropy entities. But this would be unfavorable for both the Homeworld and the Seed, because after all, he received the coordinates and even glanced at the world they pointed to. This established a certain connection with that world. To think this connection is one-way is extremely naive. Remember the great Law of Reversible Discovery: If you can see a low-entropy world, that low-entropy world will eventually be able to see you too – it’s only a matter of time. So, waiting for others to do everything is dangerous. Singer believes that by having “glanced” at the target world, they have established a connection and exposed their own trail. At such a time, if they don’t immediately destroy all possibility of being discovered, there is a risk of being traced – it’s only a matter of time. Here, the author writes that the observed world will eventually look back at you – we only need to simply connect this with Singer’s earlier action of “tracing the cleanser” to realize that not only will the observed world look back, but other civilizations lurking in the cosmic deep sea, including many advanced civilizations, might also attempt to trace you. So the question arises: The Trisolaran invasion of Earth was based on mutual silence. After the first “singing” (broadcast) and the Monitor’s well-intentioned reply “Do not answer!”, the entire universe knew the two civilizations were only 4 light-years apart – lacking only precise coordinates. Exposing either coordinate would simultaneously expose the other. Trisolaris and Earth operated under this basic tacit understanding: one silently invading with its mouth shut, the other silently resisting with its mouth shut. This led to the Deterrence Era and the story of The Dark Forest. Now the problem arises: Trisolaris insisted on invading, the Earth Fleet broadcast the coordinates, and the stagnant water was stirred up. When will the Dark Forest strike arrive? In the original text, Sophon’s tea house Q&A makes it very clear: while there’s likely still some time, it’s uncertain because it “could arrive at any moment.” Now let’s assume Trisolaris didn’t immediately flee the vicinity of Earth but left a few warships to cleanse human civilization. How would they cleanse? First, the simplest and most direct photoid strike is impossible. The reason, explained at length in Death’s End, has already been covered. That leaves only two ways: First, land troops on Earth, find and kill every single human, search the entire solar system, turn over every satellite, check every large rock, kill all humans they can find. Second, dual-vector foil, dimensional reduction strike. Trisolaris obviously doesn’t have the second option. And the material resources and, most crucially, the time required for the first task would be incalculable. They could certainly do it, but the key is time. “A Dark Forest strike could arrive at any moment.” So the crucial question arises: If some advanced civilization hidden in the cosmic deep sea launches a strike against Earth while Trisolaran warships are still in the solar system, would that advanced civilization trace the source and, crucially, the destination of the Trisolaran fleet? They absolutely would. See the original text, the rules of the Singer civilization state it clearly, as quoted earlier: He initiated a Master core process to trace the source of the mass point that killed that star. This is a task with an almost zero probability of success, but protocol requires it. “Protocol requires it.” The Trisolaran Second Fleet leaving a few warships indeed has a chance to destroy human civilization. But simultaneously, it leaves behind the risk of themselves being observed by others. This risk is not only significant but, once seen, becomes certain. Because the Trisolaran Second Fleet has a clear source – the Trisolaran coordinates. It has clear acceleration/deceleration nodes – slow fog traces. Thus, it has a clear destination. For an advanced civilization, if they can’t figure out the relationship between this slow fog and Earth, that’s one thing. But once they clearly discover that the fleet causing this slow fog is related to both Earth’s and Trisolaris’s coordinates, then using the position of the slow fog around the solar system, they can easily locate the Trisolaran Second Fleet. This isn’t cleansing Earth civilization; this is seeking death. If the above is just the reader’s “interpretation,” then I will now quote several passages from the original text to prove to you that even the author himself thought this way. Read the original, the scene of Yun Tianming and Cheng Xin’s remote video chat. This chat was strictly monitored by the Trisolaran world. When Yun Tianming said something with “risk tendency,” a yellow light would flash. Saying risky content would trigger a red light directly, killing Cheng Xin. Therefore, the following yellow light segments are all content the Trisolaran world considered to have “risk tendency.”
First instance:
Yun Tianming bent down, grabbed a handful of black soil, and let it slowly trickle through his fingers. The falling black soil sparkled with crystalline points of light. “This is made from meteorites, soil like this…”
Green light off, yellow light on.
Second instance:
“The wheat looks wonderful, ready for harvest?”
“Yes, the harvest is good this year.”
“Harvest?”
“Oh, when the engine runs at high power, the harvest is good; otherwise…”
Yellow light on.
Third instance:
“Then, what about your experiences? Is there anything you can tell me?” Cheng Xin asked. This was a naked risk, but she had to take this step.
“Hmm… Let me think…” Yun Tianming pondered.
Yellow light on. This time, the light came on before Yun Tianming said anything substantive. It was a severe warning.
Clearly, the third yellow light was the Trisolarans losing patience, issuing a severe warning to Cheng Xin and Yun Tianming. So we focus on the first two instances: What exactly made Trisolaris so wary? I won’t beat around the bush; I’ll interpret directly.
First content: Meteorite soil capable of growing wheat, piled into a “half-acre wheat field (original text),” implies the fleet once reached such meteorite clusters.
Second content: “Harvest” (年景) means the engine runs at high power. High engine power implies acceleration/deceleration. So, “when the harvest is good” means when the engine was accelerating or decelerating at full power.
Looking at both contents together implies: Where the fleet has been, and when it performed high-power acceleration/deceleration. It was precisely these two pieces of information that made the Trisolaran world extremely wary and sternly warned Yun Tianming to “not speak like this anymore (original text).”
Therefore, understanding this passage makes it clear that Trisolaris could not leave a few warships in the solar system, where “a Dark Forest strike could arrive at any moment,” creating the risk of being observed by advanced civilizations. Compared to where they’ve been and when they accelerated/decelerated, actually leaving warships behind, creating slow fog nodes? That would be disastrous! See the original text:
But mainly fear. With fear, the coordinates become sincere – for all low-entropy entities, fear is the guarantee of survival.
For all low-entropy entities, fear is the guarantee of survival.
Comment 1:
Life pursues survival, not revenge, unless revenge benefits survival.
Looking at life on Earth, even a rabbit bites when cornered, indicating that on Earth, genes for revenge benefit survival, hence they persist.
But in interstellar space, it seems a different survival logic applies.
Comment 2:
Broadcasting meant mutual assured destruction. The Trisolaran Second Fleet had no spare attention to deal with Earth anymore, let alone take on the risk of exposure. Escaping quickly was the right path.
Comment 3:
Earthlings hate the Trisolarans, but the Trisolarans don’t hate Earthlings. On the contrary, they even “admire Earth civilization.” Eliminating humans was a purely rational judgment to “seize living space” (actually alluding to Japan and China). Since the Dark Forest strike had arrived, continuing to kill Earthlings, towards whom they held no hatred and who were about to perish anyway, was meaningless. The Trisolarans preferred to let the remaining humans face their end with some dignity, as a respect for the “civilizational mentor.”
Comment 4:
In the scene where Yun Tianming meets Cheng Xin, information about technology or dimensional reduction might not have been what the Trisolaran fleet was overly concerned about; information potentially revealing the fleet’s movements was what they were extremely wary of.
Comment 5:
I think it’s because the Second Fleet itself is now a nomadic fleet; its strength can only decrease, not increase. Leaving a few ships behind to glass Earth offers no benefit to the Second Fleet itself, nor any aid to the Trisolarans. Moreover, if those ships rejoin the fleet, they risk exposing the main force’s location. If they don’t rejoin, they are a total loss. For a Second Fleet needing to face many future dangers, this is either dangerous or wasteful. It truly has no point.
