In my follow-up to James Manzi’s manifesto, I brought up a notion that I call soft rule-utilitarianism. In the comments, Manzi interpreted this as being close to what I would call hard rule-utilitarianism.Suppose we are soldiers on patrol and a grenade lands in the middle of us. If I dive away from the grenade, I will avoid major injuries, but many of my fellow soldiers will die. If I dive onto the grenade, everyone else will be saved but I will die. A hard rule-utilitarian would say that I should dive onto the grenade. What I am calling a soft rule-utilitarian would dive away.

X is a soft rule-utilitarian if X is willing to make a small sacrifice in a situation where similar sacrifices by everyone can benefit X. Diving on the grenade is too much of a sacrifice.

A soft rule-utilitarian might refrain from donating to help the people suffering in a distant country. A hard utilitarian would make the donation. A soft rule-utilitarian says, “Even if a lot of people donate to the distant sufferers, that will not benefit me, so I will not do it.”

My point is not to hold up the soft rule-utilitarian as a paragon of virtue. On the contrary, my point is to say that soft rule-utilitarianism can be a realistic expectation. On the other hand, as Manzi suggests, assuming that individuals are as virtuous as what I call hard utilitarians amounts to assuming away the problem of social cohesion.

My soft rule-utilitarian might be called self-interested with an understanding that following rules can be a good idea. Perhaps rule-self-interested would be a more informative label.

To take another example, my daughter who was in Tanzania last summer made the observation that when an African on his way to some destination bumps into a friend, the African is much more likely than an American to interrupt his errand and spend hours talking with the friend. On the one hand, that is charming. On the other hand, this makes Africans relatively unreliable in terms of showing up on time, and that in turn creates problems for efficiency and productivity, because timeliness is a basic element of coordination. The rule “show up on time” is consistent with soft rule-utilitarianism. It involves a relatively small sacrifice, and having everyone follow it makes me better off.

The example I gave in the earlier entry of not pulling onto the shoulder to gain an advantage in a traffic jam has the same properties. I do not sacrifice very much by staying in my lane, and I definitely benefit if everyone does the same.

I am dwelling on this issue because I think it helps to pin down the notion of social cohesion. We have social cohesion when people follow rules that produce large benefits when they are widely followed, even though following the rules can involve minor short-term sacrifices . We have a loss of social cohesion when people lose their willingness to follow such rules.

For example, I believe that following the rule of not using four-letter words has some advantages. Restraining oneself from cursing helps to show respect for others, and if everyone exercises such restraint, then everyone feels more respected. This rule has broken down over the past several decades. I do not think that this breakdown is a major tragedy, but I think it represents a small reduction in social cohesion. Note that I do not think that anything would be gained by government coercing people into restraining their use of four-letter words. But I am sympathetic to enforcement in other contexts, such as parents enforcing rules against cursing by their children.

Other rules are clearly more important. If people stop believing in showing up on time, that would represent a big drop in social cohesion. If people decide to practice ethnic discrimination in their everyday economic transactions, that would represent a big drop in social cohesion. Incidentally, by the same token, “buy local” represents a drop in social cohesion.

What I want to get away from is idle speculation of the sort, “If we allow economic inequality to grow, we will lose social cohesion.” Instead, I want pundits to have to specifiy the types of rules that people are likely to stop following if economic inequality increases, and to provide evidence for the belief that those rules will break down.