On September 19, 480 B.C., the ancient world faced a pivotal battle. Under the command of the despotic King Xerxes, a fleet of Persian warships had converged off the Greek coast near Piraeus, the port city that served Athens. Known as "triremes" because they were propelled by three tiers of oarsmen, the ships could achieve unprecedented speed, maneuverability, and ramming power. Some 600 to 1000 of them waited at the entrance to the narrow channel separating the Island of Salamis from the Greek mainland.
Already Xerxes' land forces had conquered the mainland, plundering Athens and destroying its temples. In anticipation of the Persian conquest, Athenian citizens had evacuated to Salamis. Within the narrow strait, Athens and allied Greek city-states sheltered only about 300 triremes, on which their hopes lay for safety from the Persian invaders. If Xerxes' navy entered the channel and successfully overcame the defenders, it would meet up with the invading land forces and vanquish the refugees on Salamis, nearly completing the conquest of the Greeks. On the mainland, within sight of the narrow channels, Xerxes himself had his minions erect a tall throne, from which he could view the sea battle expected the next day. (1)
The protagonists in the impending battle were faced with momentous decisions under difficult conditions that I shall call precariousness. I do not mean what many readers may be inclined to presume--I do not mean that they faced complex risk under uncertainty. Had they faced only risk, their sole option for rationally responding to it would have been probabilistic risk assessment. Their failure to rely on risk analysis would, then, merely have reflected the ignorance we are led to expect of people of their times. I contend, however, that they faced not risk as we usually think of it, and not even risk under extreme uncertainty and complexity, but rather precariousness. Precariousness has constituents--volition, fortuity, particularity, and others--that modern risk analysis does not help us elucidate. Using the Battle of Salamis as my ongoing example, I shall argue that precariousness provides the rationale for the exercise of the classical virtue of prudence (alongside modern analytical skills) in decision making. The ancient Greeks and especially Aristotle recognized prudence as a mode of ethical leadership adapted to precariousness. Through the whole essay, I mean to lend credence to the proposition that, in the face of the catastrophic threats we now face, we can once again find direction in the enduring prudential tradition.
Returning to the Persian threat to Greece, let's put ourselves in the position of an Athenian leader sincerely agonizing over what must be done to protect fellow citizens from catastrophe. We should envision him either on the eve of battle, when decisions had to be made under immediate duress, or some years before, when steps could still have been taken to avert war or to strengthen defenses. For that earlier decision point, we can focus on 483 B.C., three years before the Persian triremes loomed near Piraeus, when a newly discovered load of silver had just enriched Athens' coffers. How should the windfall be invested, perhaps to make the city safer from future threats? And on September 19, 480, the eve of the potentially catastrophic battle, our decision maker would have to agonize again. What tactics would protect Athenians from further loss or even regain their freedom?
In our times, under the influence of the doctrine called "risk analysis" (and its variants), the advice to Athenians would likely take the following form: Figure out the likelihoods of various enemy actions, assess the costs and benefits of courses of action to be taken against enemy moves, and thereby pick the most advantageous course. This advice would not have served Athenians well enough, nor would it for the great dangers we now face. In our time, threats from weapons of mass destruction in the hands of terrorists similarly subject us to extreme indeterminacies. The decision-making dilemmas they pose are not resolved by modern risk analysis, for reasons that Aristotle's monumental work sets out.
Writing more than a century after the incident described above, Aristotle puzzles over our capability of making a true statement today about a contingent future event. His example is a sea battle tomorrow. Possibly he was thinking of that very eve, when Europe's future hinged on the culminating engagement in the Greco-Persian War. (2) Aristotle writes that "it is necessary for there to be or not to be a sea-battle tomorrow." That's plain and unremarkable. Yet there is something curious about it: a statement that there will be a battle tomorrow is not true today; at the same time, a statement that all will be peaceful tomorrow is not true today. September 20 arrives and a battle takes place. Does the statement of September 19 suddenly become true? Aristotle says no. "Here both possibilities are open...." (3) The state of the world is compatible with either of two futures, one containing the battle and the other not; the future is yet undetermined. (4)
Whether in battle or in other practical situations, we must make decisions in the face of such indeterminacy. It may be that we are unsure of what will happen because we lack enough reliable knowledge. But this is not what Aristotle appears to mean. He seems to mean that, even with lots of good information at our disposal, there are situations in which the possibilities remain open. What's more, our decisions today could in themselves influence the eventual outcome. The future is yet unresolved. Were it not so, Aristotle writes, "there would be no need to deliberate or to take trouble (thinking that if we do this, this will happen, but if we do not, it will not)." (5)
As a start, this is what I mean by precariousness: the predicament we face in a dangerous situation, in which outcomes are indeterminate, or at least are indeterminate as far as we know, and our own volition can influence the outcome. But that is only a start. In search of a fuller description, let's examine the Battle of Salamis, which did indeed take place on September 20.
The battle turned out to be the decisive event at which a fractious alliance of Greek states led by Athens and Sparta turned back the Persian tyrant's invading forces, saving Europe from foreign domination and setting the stage for the Greek golden age and the flowering of democracy. For generations to come, right down to Aristotle's establishment of his school 150 years later, this battle would be regarded by Athenians as a crucial moment in their history. (6) The very purpose of the prudential tradition is to prepare men and women with the deliberative capacity to decide how to act in such situations.
Aristotle and Prudential Thought
Aristotle's theory (7) of decision making appears mainly in Nicomachean Ethics, a compilation of ideas arranged in somewhat haphazard fashion after his death (possibly by his son, Nicomachus). (8) Though the work is applicable to many kinds of decisions, including decisions for oneself and one's household, Aristotle is especially concerned about decisions on the community's behalf, "for while it is desirable to secure what is good in the case of an individual," he writes, "to do so in the case of a people or a state is something finer and more sublime." (9)
Aristotle seems especially to have in mind decisions on which life and community existence hinge. "Of what, then, are the terrors with which the courageous man is concerned?" he asks. (10) He may have to "endure dreadful experiences," such as death at sea or terrible illness, or conditions in which danger is the greatest, as in warfare or outbreaks of disease (11) or in earthquake and inundation. (12) Ancient Athenians had much reason to have to come to terms with the possibility of disaster. (13) Wars were frequent, rarely more then ten years apart. Defeat could mean the city's destruction, the looting of its treasures, and its citizens' subjugation or enslavement.
As thoughtful Athenians realized, a war's outcome depended on military intelligence, strategy, and relative power, but also on chance. It could be a chance storm driving a fleet off course, a chance forest fire that reveals your troops' strength, or a wartime outbreak of pox in the city, with its terrifying pustules and enormous toll in lives, destroying the citizens' morale. (14) Oracles could be consulted and gods propitiated to guard against such misfortunes, but the oracles were not about to be pinned down to specifics and the gods were caught up in their own intrigues, whose outcomes mortals might well fear. Though there was a belief in destiny, it was not thought to be settled once and for all by an omnipotent and eternal being, but was subject to Luck, herself a deity who could be supplicated but, even then, couldn't quite be relied upon. Facing danger, a human agent is left to his or her own devices, making tough decisions under harsh constraints.
Despite the difficulties of decision, Aristotle believed that there were leaders who were models of prudent conduct. (15) Such a leader knew when to invest in temples to uphold the city's honor even in tenuous peace, but also knew when to send out his fleet to protect the city from enemies bent on its annihilation and when to rally the citizenry during devastating plague.
Before proceeding, let's step back, as Aristotle does. Decisions are not always made under precariousness. Even ancient Greeks had (or thought they had) reliable general knowledge about logic, the calendar, the rising and setting of heavenly bodies, mathematics, the training of athletes, laws and government institutions, and to some modest extent nature and even health. (16) Some of it was rudimentary scientific knowledge. Aristotle, who was quite interested in the science of medicine, could confidently advise what many of us still have not...