There are a few situations in which I follow self-imposed rules that balance between my self-interest and the interests of others. More accurately, however, they balance my self-interest against my sense of guilt. Here are some examples:

• When I cross a street on foot I make a point of never obstructing traffic that has the right of way. I am happy to assert my right to cross with a light or in a cross walk. I also don't mind crossing against the light or otherwise in violation of technical rules, so long as nobody's travel is impeded.
  
• In a coffee shop I never take a table until I have gotten food or a beverage. My reasoning is that if everyone did this half the tables would be taken up by people waiting in line. If nobody does it the tables are used with the maximum efficiency.
  
• When I'm in the elevator in my building I don’t hold the doors just because I hear someone coming in the outer door, but I always hold the door if the person asks or if I see the person coming towards the elevator. Someone just coming in the outer door may want to get their mail, and even read their mail, instead of going directly to the elevator.

These examples resonate to some extent with Kant's idea of living by rules that one can will to be universal. As a driver I hate it when a jaywalker forces me to slow down, I'm annoyed when I can't find a table because someone in line behind me reserved it, and of course I don’t like to see the elevator close in my face. But on the other side, these rules allow me to jay walk so long as traffic isn't obstructed, to seize a table the minute I have my drink (even if I'm also waiting for a sandwich) and to ruthlessly allow the elevator doors to close so long as I haven't seen the person who is coming. I don't claim any universal validity to these rules of behavior, but they do feel right to me.

A more complex situation arose at Mass College of Art eight or so years back. The issue was ludicrous, but the dispute which it engendered was passionate. One group of students claimed that everyone should remove lint from the filter on the driers after doing their laundry while a second group felt that everyone should clear the lint before doing their own load. When lint was left in the machine the first group was outraged, while the second group considered this appropriate. How should such an issue be resolved? Majority vote is of course one approach, but in this case it is possible to reason to a fairly objective answer.

The first question is what would happen if everyone followed each of the proposed rules. Both work fine if there is 100% compliance: in one case everyone removes the lint before and in the other everyone removes the lint after their load. Each person does the same amount of work. There is a small benefit to the "after" model in that each person handles only his own lint and not someone else's.

The next question, however, is what happens if some people don't follow the prevailing rule. In this case the results are very different. In the "before" model the consequence falls squarely on the person who doesn’t comply -- his laundry doesn't get as dry. Everyone else is unaffected (the additional lint from two loads being no more difficult for the next person to remove than that from one load). In the "after" model, however, the occasional rule breaker gets a clear benefit -- he doesn't have to even check the lint filter because everyone else is following the rule. The adverse effect falls on the next person, whose laundry doesn't get as dry. Consequently there is a penalty for breaking the "before" rule, but there is an incentive, and no penalty, to break the "after" rule. While in a world of perfect compliance the two rules are similar, in a real world of incomplete compliance the "before" rule is stable, while the "after" rule is unstable.

The fact that the burden of the "after" rule falls on the next user has a further consequence. Once it becomes clear that some people aren't complying with the rule a user who cares (there seem to have been a lot of them at the MCA!) is forced to check the lint filter before doing the load (in case the previous person was a rule breaker) and also to clear the filter after the load (to comply with the rule). This is far worse than either consistent rule, since it requires a rule-abiding person to do nearly twice the work.