The Northern Expeditions Problem: Why Two Different Men Would Have Marched the Same Road

In 227, Zhuge Liang wrote a memorial to the young emperor Liu Shan explaining why he was about to lead an army north. The document survives, and Chinese schoolchildren still memorize passages from it, among them this line: 受命以来，夙夜忧叹，恐托付不效，以伤先帝之明, “since receiving this charge I have been anxious day and night, fearing that I might fail the trust placed in me and so tarnish the late emperor’s judgment.” The memorial does not pretend the odds are good. It calls the province of Yi 疲弊, exhausted, and the moment 危急存亡之秋, a time when survival itself hangs in the balance. Wei held more territory, more people, more grain and a defensible heartland. Shu Han held a mountainous province with a fraction of those resources. Zhuge Liang went anyway, and kept going: five campaigns north over the next seven years, none of which held its ground, until he died in camp on the last of them in 234, still trying.

Tradition treats this as heroism, though not of a modern kind. What the memorial names is 忠, loyalty, a duty owed to a dead emperor, not freedom asserted against history. Translated into another vocabulary, however, the duty takes the shape Albert Camus found in Sisyphus, condemned to push a boulder up a mountain forever, knowing it will roll back every time. Camus did not conclude that Sisyphus should stop. He concluded that the pushing, undertaken in full knowledge of its futility, is where whatever freedom a person has is to be found, since it was never going to appear in the outcome. On this reading Zhuge Liang’s campaigns were not a miscalculation. They were closer to a position, argued five times over with an army instead of a brush: that a person’s values can remain his own even after history has decided the ending.

There is a less romantic explanation, and it does not require Zhuge Liang to anticipate Camus by seventeen centuries. Shu Han’s claim to legitimacy rested on being the true continuation of the Han, a government in exile rather than a breakaway state, and that claim held only so long as the state kept acting like a government still fighting for the whole empire. A Shu Han that stopped marching north had not merely given up on winning. It had admitted that it was one more regional power, no more legitimate than Wei or Wu, and that admission would have dissolved the loyalty the regime depended on faster than any lost battle. Read this way, the campaigns were not a wager on victory at all. They were the price of keeping a claim alive, paid one expedition at a time, and a purely strategic ruler with no interest in freedom, dignity or Camus would have made the same five marches for the same reasons.

Here the free will problem turns up in a military campaign rather than a seminar room. There are two complete explanations for the same five marches. In one, a man’s values stand against the current of history. In the other, a rational minister manages a regime’s survival under pressures he never chose. Nothing in the marches decides between them, because both predict the same behavior. Zhuge Liang writes the same memorial, takes the same road and dies in the same camp under either description. Even his death does not break the symmetry. A chancellor who visibly withdrew from a losing war would have announced Shu Han’s decline as loudly as one who died leading it, so the political explanation needs his death in the field as much as the philosophical one does. The deadlock is close to what David Hume argued in the eighteenth century: that liberty and necessity are not opposites. An act can be caused through and through, by upbringing, loyalty and political pressure, and still be free in the only sense Hume thought worth having: done according to the agent’s own will. From outside, the caused man and the free man are one man walking north.

What makes this a harder version of the problem than the empty fort, rather than the same problem restaged, is the evidence. The empty fort offers only behavior, a retreat no one could question afterward, in a story that may never have happened. Here there is testimony, in Zhuge Liang’s own words, and it does not help. The anxious, dutiful voice of the memorial is the voice a man freely choosing his duty would use. It is also the voice of a man whose sense of duty was formed for him, by a dead emperor’s expectations and a claim to legitimacy he inherited without choosing. Sincerity is not the tiebreaker it appears to be from outside.

The memorial itself may be the better tribute to what Zhuge Liang did. It does not argue that the campaign will succeed. It argues that the attempt is owed, whether or not anyone could later prove the attempt free or caused. Whichever description is correct, a man who understood the odds as well as any modern reader still marched, five times, into ground he knew would not hold. Determinism may well explain why he marched. It offers no way to explain away the fact that he did.