Caesar crosses the Rubicon
Part of a Series on the Philosophy of History
On 10 January 49 BC — 2,073 years ago — Caesar crossed the Rubicon with the 13th legion. This is one of the most notable dates in western history, and it’s symbolic on many levels. Those who dislike history because it was taught to them as a dreary recitation of names, dates, and places might remember this because we have the name of Caesar, the date of 10 January 49 BC, and the place, the Rubicon river. Caesar is supposed to have said, “The die is cast” when he made the crossing. Some sources say that Caesar said this in Greek, and one source said that the phrase came from a lost comedy by Menander.
The Rubicon river was the legal boundary between Rome and the provinces, and it was illegal for Caesar to cross the river with his army. The Romans were well aware that it wasn’t a good idea for a conquering general to enter the capital with his troops, unless he had come for a triumphal procession explicitly granted by the Senate to celebrate a military success. Caesar did eventually get his triumph, in fact, he got four of them, but not until 46 BC, after the Civil War. Earlier, before the civil war, Caesar had been offered the choice between a triumph and a consulship, and he took the consulship. The Romans took their triumphs seriously; as we can see, they were a political bargaining chip.
Crossing the Rubicon ultimately initiated a civil war that eventually ended the Roman Republic and ushered in the Roman Empire, though, even when Octavian became the first emperor, Rome maintained the fictions of the Republic, which were politically powerful, and which remained politically powerful for some time to come. So, for the sake of “optics,” Octavian, later Augustus, called himself “first citizen” (“princeps”) and not emperor. It wasn’t until hundreds of years later that the emperors openly called themselves emperors. And Octavian as emperor was the same Caesar Augustus who decreed that all the world should be taxed.
In the traditional approach to history that emphasized names, dates, and places, an event like Caesar crossing the Rubicon was one of those names, dates, and places that one was supposed to memorize, as it constitutes a paradigmatic example of an historical event. It’s also representative of a moment in history when things might have gone differently, and this based on the decision of a single man. Thus the event of Caesar leading his army across the Rubicon exemplifies the decisive and definitive role of individuals in history, and even the role of human free will in history. If Caesar had chosen not to lead his army across the Rubicon, and had turned back, Roman history, and thus world history, could have been very different.
Appian of Alexandria, a Greek historian working in Rome during the second century AD, wrote in his The Civil Wars that Caesar acknowledged the two possible courses of action open to him at that moment:
“When his course brought him to the river Rubicon, which forms the boundary line of Italy, he stopped and, while gazing at the stream, revolved in his mind the evils that might result from his crossing it with arms. Recovering himself he said to those who were present, ‘My friends, stopping here will be the beginning of sorrows for me; crossing over will be such for all mankind.’ Thereupon, he crossed with a rush like one inspired, uttering the common phrase, ‘Let the die be cast’.”
The path not taken by Caesar, which, according to Appian, would have been the beginning of sorrows for Caesar, and implied was that it would have been a sparing of sorrow for all mankind, is for us a unrealized alternative history. We call such a scenario a counterfactual, or a contrary-to-fact conditional. This is the “What if…?” element in history, and it’s not only an interesting exercise in speculation, but also presents us with numerous interesting philosophical problems.
The episode of Caesar crossing the Rubicon exemplifies many ideas that have been central to western civilization — individualism, free will, the efficacy of the individual, the contingency of history, the idea of unrealized possibilities and thus unrealized potential, and the idea of a decisive, defining moment in history which made the world as it is today, but which might have gone in a different direction. We may compare this latter idea — the defining historical moment — to the idea of a crucial experiment — experimentum crusis — in the natural sciences. There is a sense in which the experimentum crusis of the social sciences is a defining historical moment.
Historical action is the acting out of scientific experimentation. In experimentation, the observer remains constant, part of the controlled conditions of the observation, while the independent variable is allowed to run its course while the dependent variable in the experiment is monitored. In historical action, the agent is immersed in the world observed, and so becomes the dependent variable responding to the independent variables encountered in action. Historical action, then, is role reversal in experimentation. Action is how we discover our efficacy in the world, as experimentation is how the world’s efficacy is discovered by us. Caesar, in taking action, defined the moment by crossing the Rubicon and letting the chips to fall where they may, and discovering, as a consequence, the course of history revealed by this action.
In a crucial experiment, a theory is confirmed or disconfirmed. In a defining historical moment, a history is confirmed or disconfirmed. By crossing the Rubicon, Caesar confirmed the history of which this event is not merely a part, not merely one of many events in a sequence of events, but an event that shapes later events definitively. Was Caesar committed to this action by his prior decisions and the course of his life? I suspect that everyone who marched with Caesar to the Rubicon expected him to cross. I’m not saying that Caesar was locked into his decision, but crossing the Rubicon was implied by marching the 13th legion to the river.
It would be surprising if someone like Julius Caesar marched an army to the Rubicon, only hesitate at the river’s edge, and then decided not to cross. However, we do have the example of the Emperor Caligula, who, during his campaign in Gaul in AD 39–40 marched his forces to the English channel, but, instead of staging an invasion, he ordered his soldiers to pick up shells on the beach. This episode is rather obscure, and historians don’t agree on its significance, and only 3 years later in AD 43 the emperor Claudius began the conquest of Britain, so this expedition by Caligula may have involved reconnaissance since lost to history. And the obvious comment to be made here is that Caligula was not a man like Julius Caesar, so that to compare Caesar’s march to the Rubicon to Caligula’s expedition to the English Channel, sometimes called Caligula’s War on the Sea, isn’t a helpful comparison.
How Caesar himself understood his decision to cross the Rubicon is implied by his career before and after the event, but we have no account from Caesar himself if he struggled with the decision. Caesar was murdered before he could write his memoirs, so a Caesarian account of the crossing of the Rubicon is for us as much of a counterfactual as a world in which Caesar didn’t cross the Rubicon. Because they are lost to history, are Caesar’s thought processes in making the decision to cross the Rubicon beyond our ability to reconstruct? I raise this question because of its relevance to Collingwood’s philosophy of history.
In the Epilogomena to his The Idea of History, “Human Nature and Human History,” Collingwood uses Caesar’s crossing of the Rubicon to illustrate his distinctive form of idealism in history. In my immediately previous episode on Jean Hyppolite I mentioned that Collingwood made a distinction between the inside and the outside of history, because Hyppolite also makes a distinction between interiority and exteriority, but he said that, for Hegel, nature is merely interior and has no outward expression in history. Collingwood begins his discussion of Caesar by employing this distinction:
“The historian, investigating any event in the past, makes a distinction between what may be called the outside and the inside of an event. By the outside of the event I mean everything belonging to it which can be described in terms of bodies and their movements: the passage of Caesar, accompanied by certain men, across a river called the Rubicon at one date, or the spilling of his blood on the floor of the senate-house at another. By the inside of the event I mean that in it which can only be described in terms of thought: Caesar’s defiance of Republican law, or the clash of constitutional policy between himself and his assassins. The historian is never concerned with either of these to the exclusion of the other. He is investigating not mere events (where by a mere event I mean one which has only an outside and no inside) but actions, and an action is the unity of the outside and inside of an event. He is interested in the crossing of the Rubicon only in its relation to Republican law, and in the spilling of Caesar’s blood only in its relation to a constitutional conflict. His work may begin by discovering the outside of an event, but it can never end there; he must always remember that the event was an action, and that his main task is to think himself into this action, to discern the thought of its agent.”
But can the historian ever truly think himself into the action of a past historical agent? Can we ever know the thought of the agent of history to a degree that it would be adequate to the needs to history? As Caesar was marching the 13th Legion to the Rubicon, we could see this as the beginning of the unfolding of a sequence of events that will culminate in a civil war and the effective end of the Roman Republic, but without knowing the history of Caesar’s thoughts in detail can we know whether he had any doubts during his march to the Rubicon? Would it have been possible to Caesar to make a different decision on the banks of the Rubicon? Was Caesar having any doubts or second thoughts? To know this we would have to know Caesar’s thoughts in a degree of detail that is inaccessible to us. If Caesar had journaled like a Puritan, we could well entertain the possibility of reconstructing his thoughts on the march to the Rubicon. But that wasn’t Caesar’s style at all.
Caesar’s accounts of his own campaigns, famous as introductory Latin texts, are also famous for this laconic style. Veni, vidi, vici. I came, I saw, I conquered. This is dramatic stuff, even legendary, but it’s not the level of detailed point of consciousness narration necessary to the reconstruction of the thoughts of Caesar as he rode with his troops to the banks of the Rubicon. Suetonius, in fact, credited Caesar with hesitation at the Rubicon:
“…overtaking his cohorts at the river Rubicon, which was the boundary of his province, he paused for a while, and realising what a step he was taking, he turned to those about him and said: ‘Even yet we may draw back; but once cross yon little bridge, and the whole issue is with the sword.’ As he stood in doubt, this sign was given him. On a sudden there appeared hard by a being of wondrous stature and beauty, who sat and played upon a reed; and when not only the shepherds flocked to hear him, but many of the soldiers left their posts, and among them some of the trumpeters, the apparition snatched a trumpet from one of them, rushed to the river, and sounding the war-note with mighty blast, strode to the opposite bank. Then Caesar cried: ‘Take we the course which the signs of the gods and the false dealing of our foes point out. The die is cast,’ said he.”
This sounds like something we would expect to read in a medieval historian, with Caesar waiting for a sign from heaven before he would cross. The Romans could be as superstitious as any people, but the fact that this sign of the gods recorded by Suetonius isn’t nearly as well known as the crossing the Rubicon shows us how little is known of Caesar’s thoughts on the occasion.
The Collingwoodian project often must take the form of inferring thoughts from the exterior of events, and that can never be satisfactory. However, we can imagine ways in which it might be made more adequate. If we could construct an elaborately detailed computer simulation in which individuals could upload themselves into the program and play the part of Caesar, they might become so immersed in the role that came close to reproducing the thoughts of Caesar as he approached the Rubicon. This would especially the case if all of Caesar’s life up to the point could be simulated. An exhaustive simulation would capture everything known about the exteriority of events, leaving the thought processes as the undetermined variable that they player would experience as they lived the life of Caesar vicariously.
Since I’m imagining simulation technology we don’t have, I might as well further imagine that the mind of the person uploaded in the simulation and experiencing the career of Caesar could be made accessible and recorded for later study. In this way, multiple runs of the simulation with multiple individuals playing the part of Caesar could be compared. Perhaps in some simulations Caesar would cross the Rubicon, and in other simulations Caesar would take the counterfactual course of history and not cross. Those scenarios that most closely match actual historical events would then be the basis for reconstructing Caesar’s actual thoughts in deciding to cross the Rubicon.
I can think of many ways to criticize this idea, but even if we can’t yet act upon it, it’s a thought experiment that’s worth pursuing. I would argue that Collingwoodian history as the reconstruction of the thoughts of past historical agents is itself one big thought experiment, and that this thought experiment becomes more effective the more the more comprehensive it becomes. An erudite historian who knows everything of relevance about Caesar offers a certain level of fidelity for the reconstruction of Caesar’s thoughts, but an immersive experience might reveal to participants aspects of the history only revealed from the inside, as it were, living through the events themselves, for oneself. This is what historical reenactment seeks to do, again, to a certain level of fidelity. The question then becomes: how far can we push that fidelity if the proper tools are made available to us? This, I think, is in the spirit of what Collingwood was suggesting, and points to ways in which we might make our historical accounts more adequate than they are.
