I find the debate over the existence of a god intrinsically interesting. Among the many arguments that exist, one argument in favor of a god’s existence I find fairly clever is Alvin Plantinga’s modal ontological argument. I’m not going to get too into the weeds over the finer details of that argument here, but in very simplified and condensed form, it can be described as follows. After offering a definition of “god,” the argument simply starts with the singular premise that the existence of such a being is at least possible. From there, it utilizes modal logic to go through a series of steps to reach the conclusion that the existence of such a being is necessarily true. The argument is logically valid, and everything follows deductively from the fairly modest premise that god’s existence is merely possible. This means that to deny the conclusion of the argument, it becomes incumbent on you to dispute that first and only premise, and offer a positive argument that god’s existence is impossible. 

One of the biggest counters to the modal ontological argument is to point out that there is a symmetrical argument that can be constructed to reach the opposite conclusion. That is, you can also start with the fairly modest premise that it’s simply possible that no god exists, and using the same logically valid steps, reach the conclusion that the non-existence of a god is necessarily true. In order to resolve this issue, one would need to propose some kind of symmetry breaker between these two arguments, such that we have some non-arbitrary reason to prefer one over the other. Philosophers and theologians have proposed a number of different symmetry breakers over the years – you can see a compilation and evaluation of them in this recently released paper, if you’re interested.

Why am I bringing all this up? Well, recently I posted about how I find libertarianism and classical liberalism to be more focused on reciprocity than other political philosophies. I argued that Thomas Christiano’s argument for the authority of democracy based on the obligation to show proper respect to the judgment of your fellow citizens fails because the obligation he cites (were it to exist, which is far from clear!) is reciprocal in nature. As I put it there:

Even assuming that placing one’s judgment above the judgment of others is an impermissible wrong, the situation is still reciprocal. If my fellow citizens say I must do as they have decided because if I don’t, I’m treating my judgment as superior to theirs and treating them wrongly, I can equally say that by trying to compel me to do as they’ve decided, they’re placing their judgment above my own, placing me as an inferior and treating me wrongly. The situation is reciprocal.

I also argued that Yoram Hazony’s concerns about free trade undercutting the mutual loyalty among the citizens of a nation fails to get off the ground because of the same issue:

After all, what Hazony invokes so often is the idea of mutual loyalty – and the thing about mutual loyalty is that it’s mutual. The obligation goes in both directions. So why would we say I’m failing to show Walter proper loyalty by buying from Carl? Why not say Walter would be failing to show proper loyalty to me, by insisting I buy from him despite the huge additional financial burden it would impose on me? Simply saying “mutual loyalty” does nothing to resolve this

Like the modal ontological argument, both of these situations require a symmetry breaker before they can reach the conclusions their proponents seek. And that’s what I think classical liberal and libertarian thought help bring to the table by focusing on the reciprocal nature of these situations. Invoking symmetry isn’t a semantic stopsign, designed to end conversations. It’s an invitation to carry a conversation forward by pointing out that there is a further factor requiring attention. 

In the comment section to my previous post, commenter Dylan also brought up the issue of symmetry breakers regarding externalities. Dylan points out that in many cases, people’s moral intuitions about a situation serve as a symmetry breaker. I brought up Ronald Coase’s insight about the reciprocal nature of externalities in my post – and Dylan described how widely held beliefs about particular cases will, for many people, break the symmetrical nature of the situation. As he put it:

Take the classic externality of the polluting factory, the idea that I should pay to stop the factory from polluting (or pay to mitigate my exposure) just feels wrong on a fundamental level, even if that solution would win on efficiency grounds.

I think this accurately describes how the vast majority of people would react to this situation. To tell someone “Well, why don’t you just pay that factory to install scrubbers if you’re so upset about their smoke and soot falling in your yard” just feels wrong. Most people have a strong reaction along the lines of “They shouldn’t be blowing soot on my house in the first place – why should I have to pay them to make it stop?” 

I think that in a lot of cases, moral considerations are a source of symmetry breakers. To use an easy example, my desire that my house not be burned down interferes with Pyro Pete’s desire to burn down houses. Technically, we are imposing on each other in a reciprocal, symmetrical way. But I don’t think it’s a great moral mystery to work out what a symmetry breaker is in this circumstance. Arson is wrong, therefore my imposition on Pyro Pete’s wishes is morally justified in a way that breaks the symmetry. 

Sometimes in situations where the moral obligation isn’t clear (or isn’t applicable), other sources of symmetry breakers exist. Sometimes social conventions and norms can serve as symmetry breakers. Or in the court system, one standard that’s sometimes used is the principle of the “least-cost avoider.” In this standard, if two parties are equally imposing on each other (in a way that doesn’t clearly violate some existing law or moral imperative), the responsibility to ameliorate the situation is given to whichever party faces the lowest cost of doing so. If changing the situation is a major imposition on me but only a minor inconvenience for you, then that serves as the symmetry breaker in these cases. 

The libertarian and classical liberal focus on reciprocity and symmetry isn’t born of some desire to argue that all laws or interventions are always unjustified on the grounds that every situation is symmetrical. If that was the case, libertarians would be arguing that a law preventing Pyro Pete from burning down my house is unjustified – but I’ve yet to come across a libertarian in favor of arson! But libertarians and classical liberals are correct to point out that the issue of reciprocity and symmetry exist and are important issues deserving examination. Symmetry isn’t an insurmountable obstacle – but ignoring the issue isn’t justified. To the extent that libertarians and classical liberals keep this issue raised, they are doing public discourse a service.