Intentions and consequences

The conceptual structure of game theory is illuminating. Does it also help us explain behavior? Consider the game-theoretic rationale for burning one's bridges or one's ships. This behavior could be undertaken for the strategic reasons set out in the last chapter, but also for others. In the most famous example, Hernán Cortés destroyed all his ships after arriving on the coast of Mexico in 1519, partly to prevent a conspiracy among some of his men to seize a ship and escape to Cuba, partly to add sailors to his infantry. He later wrote that by this act he gave the men the “certainty that they must either win the land or die in the attempt.” To my knowledge, there is no evidence that he also intended to signal this fact to Montezuma, as the game-theoretic rationale would require.

In fact, there is no documented instance (once again, to my knowledge) of such reasoning. The claim that William the Conqueror burned his ships upon arriving in England in 1066 seems to be a myth. Hume cites James Lancaster's attack in 1594 on Pernambuco in Brazil: “As he approached the shore, he saw it lined with great numbers of the enemy; but no-wise daunted at this appearance, he placed the stoutest of his men in boats, and ordered them to row with such violence, on the landing place, as to split them in pieces. By this bold action, he both deprived his men of all resource but in victory, and terrified the enemy, who fled after a short resistance.” The reference to the terror-struck enemy is missing in other accounts, but even if accurate would not support, in fact would contradict, the idea that the enemy fled as a rational response to a rational action. (It is also possible that Lancaster had a prudential fear that the men might retreat out of visceral fear if they were left the opportunity to do so.) Nor do other famous ship-burning episodes fit the game-theoretic pattern. When Agathocles, a tyrant of Sicily in the third century BC, burned his ships, it was because he did not want them to fall into the hands of the enemy, and because he could not spare the men to guard them.