Eight Short Studies On Excuses

The Clumsy Game-Player

You and a part­ner are play­ing an Iter­ated Pri­soner’s Dilemma. Both of you have pub­li­cly pre-com­mit­ted to the tit-for-tat strat­egy. By iter­a­tion 5, you’re go­ing hap­pily along, rak­ing up the bonuses of co­op­er­a­tion, when your part­ner un­ex­pect­edly presses the “defect” but­ton.

“Uh, sorry,” says your part­ner. “My finger slipped.”

“I still have to pun­ish you just in case,” you say. “I’m go­ing to defect next turn, and we’ll see how you like it.”

“Well,” said your part­ner, “know­ing that, I guess I’ll defect next turn too, and we’ll both lose out. But hey, it was just a slipped finger. By not trust­ing me, you’re cost­ing us both the benefits of one turn of co­op­er­a­tion.”

“True”, you re­spond “but if I don’t do it, you’ll feel free to defect when­ever you feel like it, us­ing the ‘finger slipped’ ex­cuse.”

“How about this?” pro­poses your part­ner. “I promise to take ex­tra care that my finger won’t slip again. You promise that if my finger does slip again, you will pun­ish me ter­ribly, defect­ing for a bunch of turns. That way, we trust each other again, and we can still get the benefits of co­op­er­a­tion next turn.”

You don’t be­lieve that your part­ner’s finger re­ally slipped, not for an in­stant. But the plan still seems like a good one. You ac­cept the deal, and you con­tinue co­op­er­at­ing un­til the ex­per­i­menter ends the game.

After the game, you won­der what went wrong, and whether you could have played bet­ter. You de­cide that there was no bet­ter way to deal with your part­ner’s “finger-slip”—af­ter all, the plan you en­acted gave you max­i­mum pos­si­ble util­ity un­der the cir­cum­stances. But you wish that you’d pre-com­mit­ted, at the be­gin­ning, to say­ing “and I will pun­ish finger slips equally to de­liber­ate defec­tions, so make sure you’re care­ful.”

The Lazy Student

You are a perfectly util­i­tar­ian school teacher, who at­taches ex­actly the same weight to oth­ers’ welfare as to your own. You have to have the re­ports of all fifty stu­dents in your class ready by the time midterm grades go out on Jan­uary 1st. You don’t want to have to work dur­ing Christ­mas va­ca­tion, so you set a dead­line that all re­ports must be in by De­cem­ber 15th or you won’t grade them and the stu­dents will fail the class. Oh, and your class is Eco­nomics 101, and as part of a class pro­ject all your stu­dents have to be­have as self­ish util­ity-max­i­miz­ing agents for the year.

It costs your stu­dents 0 util­ity to turn in the re­port on time, but they gain +1 util­ity by turn­ing it in late (they en­joy pro­cras­ti­nat­ing). It costs you 0 util­ity to grade a re­port turned in be­fore De­cem­ber 15th, but −30 util­ity to grade one af­ter De­cem­ber 15th. And stu­dents get 0 util­ity from hav­ing their re­ports graded on time, but get −100 util­ity from hav­ing a re­port marked in­com­plete and failing the class.

If you say “There’s no penalty for turn­ing in your re­port af­ter dead­line,” then the stu­dents will pro­cras­ti­nate and turn in their re­ports late, for a to­tal of +50 util­ity (1 per stu­dent times fifty stu­dents). You will have to grade all fifty re­ports dur­ing Christ­mas break, for a to­tal of − 1500 util­ity (-30 per re­port times fifty re­ports). To­tal util­ity is −1450.

So in­stead you say “If you don’t turn in your re­port on time, I won’t grade it.” All stu­dents calcu­late the cost of be­ing late, which is +1 util­ity from pro­cras­ti­nat­ing and −100 from failing the class, and turn in their re­ports on time. You get all re­ports graded be­fore Christ­mas, no stu­dents fail the class, and to­tal util­ity loss is zero. Yay!

Or else—one stu­dent comes to you the day af­ter dead­line and says “Sorry, I was re­ally tired yes­ter­day, so I re­ally didn’t want to come all the way here to hand in my re­port. I ex­pect you’ll grade my re­port any­way, be­cause I know you to be a perfect util­i­tar­ian, and you’d rather take the −30 util­ity hit to your­self than take the −100 util­ity hit to me.”

You re­spond “Sorry, but if I let you get away with this, all the other stu­dents will turn in their re­ports late in the sum­mer.” She says “Tell you what—our school has pro­ce­dures for chang­ing a stu­dent’s pre­vi­ously given grade. If I ever do this again, or if I ever tell any­one else about this, you can change my grade to a fail. Now you know that pass­ing me this one time won’t af­fect any­thing in the fu­ture. It cer­tainly can’t af­fect the past. So you have no rea­son not to do it.” You be­lieve her when she says she’ll never tell, but you say “You made this ar­gu­ment be­cause you be­lieved me to be the sort of per­son who would ac­cept it. In or­der to pre­vent other peo­ple from mak­ing the same ar­gu­ment, I have to be the sort of per­son who wouldn’t ac­cept it. To that end, I’m go­ing to not ac­cept your ar­gu­ment.”

The Griev­ing Student

A sec­ond stu­dent comes to you and says “Sorry I didn’t turn in my re­port yes­ter­day. My mother died the other day, and I wanted to go to her funeral.”

You say “Like all eco­nomics pro­fes­sors, I have no soul, and so am un­able to sym­pa­thize with your loss. Un­less you can make an ar­gu­ment that would ap­ply to all ra­tio­nal ac­tors in my po­si­tion, I can’t grant you an ex­ten­sion.”

She says “If you did grant this ex­ten­sion, it wouldn’t en­courage other stu­dents to turn in their re­ports late. The other stu­dents would just say ‘She got an ex­ten­sion be­cause her mother died’. They know they won’t get ex­ten­sions un­less they kill their own moth­ers, and even eco­nomics stu­dents aren’t that evil. Fur­ther, if you don’t grant the ex­ten­sion, it won’t help you get more re­ports in on time. Any stu­dent would rather at­tend her mother’s funeral than pass a course, so you won’t be suc­cess­fully mo­ti­vat­ing any­one else to turn in their re­ports early.”

You think for a while, de­cide she’s right, and grant her an ex­ten­sion on her re­port.

The Sports Fan

A third stu­dent comes to you and says “Sorry I didn’t turn in my re­port yes­ter­day. The Bears’ big game was on, and as I’ve told you be­fore, I’m a huge Bears fan. But don’t worry! It’s very rare that there’s a game on this im­por­tant, and not many stu­dents here are sports fans any­way. You’ll prob­a­bly never see a stu­dent with this ex­act ex­cuse again. So in a way, it’s not that differ­ent from the stu­dent here just be­fore me, the one whose mother died.”

You re­spond “It may be true that very few peo­ple will be able to say both that they’re huge Bears fans, and that there’s a big Bears game on the day be­fore the re­port comes due. But by ac­cept­ing your ex­cuse, I es­tab­lish a prece­dent of ac­cept­ing ex­cuses that are ap­prox­i­mately this good. And there are many other ex­cuses ap­prox­i­mately as good as yours. Maybe some­one’s a big soap opera fan, and the sea­son fi­nale is on the night be­fore the dead­line. Maybe some­one loves rock mu­sic, and there’s a big rock con­cert on. Maybe some­one’s brother is in town that week. Prac­ti­cally any­one can come up with an ex­cuse as good as yours, so if I ac­cept your late re­port, I have to ac­cept ev­ery­one’s.

“The stu­dent who was here be­fore you, that’s differ­ent. We, as a so­ciety, already have an or­der­ing in which a fam­ily mem­ber’s funeral is one of the most im­por­tant things around. By ac­cept­ing her ex­cuse, I’m es­tab­lish­ing a prece­dent of ac­cept­ing any ex­cuse ap­prox­i­mately that good, but al­most no one will ever have an ex­cuse that good. Maybe a few peo­ple who are re­ally sick, some­one strug­gling with a di­vorce or a breakup, that kind of thing. Not the hordes of peo­ple who will be com­ing to me if I give you your ex­emp­tion.

The Mur­der­ous Husband

You are the hus­band of a won­der­ful and beau­tiful lady whom you love very much—and whom you just found in bed with an­other man. In a rage, you take your hard­cover copy of In­tro­duc­tion To Game The­ory and knock him over the head with it, kil­ling him in­stantly (it’s a pretty big book).

At the mur­der trial, you plead to the judge to let you go free. “So­ciety needs to lock up mur­der­ers, as a gen­eral rule. After all, they are dan­ger­ous peo­ple who can­not be al­lowed to walk free. How­ever, I only kil­led that man be­cause he was hav­ing an af­fair with my wife. In my place, any­one would have done the same. So the crime has no bear­ing on how likely I am to mur­der some­one else. I’m not a risk to any­one who isn’t hav­ing an af­fair with my wife, and af­ter this in­ci­dent I plan to di­vorce and live the rest of my days a bach­e­lor. There­fore, you have no need to de­ter me from fu­ture mur­ders, and can safely let me go free.”

The judge re­sponds: “You make a con­vinc­ing ar­gu­ment, and I be­lieve that you will never kill any­one else in the fu­ture. How­ever, other peo­ple will one day be in the po­si­tion you were in, where they walk in on their wives hav­ing an af­fair. So­ciety needs to have a cred­ible pre-com­mit­ment to pun­ish­ing them if they suc­cumb to their rage, in or­der to de­ter them from mur­der.”

“No,” you say, “I un­der­stand your rea­son­ing, but it won’t work. If you’ve never walked in on your wife hav­ing an af­fair, you can’t pos­si­bly un­der­stand the rage. No mat­ter how bad the de­ter­rent was, you’d still kill the guy.”

“Hm,” says the judge. “I’m afraid I just can’t be­lieve any­one could ever be quite that ir­ra­tional. But I see where you’re com­ing from. I’ll give you a lighter sen­tence.”

The Bel­li­cose Dictator

You are the dic­ta­tor of East Ex­am­ples­tan, a ba­nana re­pub­lic sub­sist­ing off its main im­port, high qual­ity hy­po­thet­i­cal sce­nar­ios. You’ve always had it in for your an­ces­tral en­emy, West Ex­am­ples­tan, but the UN has made it clear that any coun­try in your re­gion that ag­gres­sively in­vades a neigh­bor will be severely pun­ished with sanc­tions and pos­si­ble en­forced “regime change.” So you de­cide to leave the West alone for the time be­ing.

One day, a few West Ex­am­ples­ta­nis un­in­ten­tion­ally wan­der over your un­marked bor­der while prospect­ing for new sce­nario mines. You im­me­di­ately de­clare it a “hos­tile in­cur­sion” by “West Ex­am­ples­tani spies”, de­clare war, and take the Western cap­i­tal in a sneak at­tack.

The next day, Ban Ki-moon is on the phone, and he sounds an­gry. “I thought we at the UN had made it perfectly clear that coun­tries can’t just in­vade each other any­more!”

“But didn’t you read our pro­pa­ganda mouthpi...ahem, offi­cial news­pa­per? We didn’t just in­vade. We were re­spond­ing to Western ag­gres­sion!”

“Balder­dash!” says the Sec­re­tary-Gen­eral. “Those were a cou­ple of lost prospec­tors, and you know it!”

“Well,” you say. “Let’s con­sider your op­tions. The UN needs to make a cred­ible pre-com­mit­ment to pun­ish ag­gres­sive coun­tries, or ev­ery­one will in­vade their weaker neigh­bors. And you’ve got to fol­low through on your threats, or else the pre-com­mit­ment won’t be cred­ible any­more. But you don’t ac­tu­ally like fol­low­ing through on your threats. In­vad­ing rogue states will kill a lot of peo­ple on both sides and be poli­ti­cally un­pop­u­lar, and sanc­tions will hurt your econ­omy and lead to heart-rend­ing images of chil­dren starv­ing. What you’d re­ally like to do is let us off, but in a way that doesn’t make other coun­tries think they’ll get off too.

“Luck­ily, we can make a cred­ible story that we were fol­low­ing in­ter­na­tional law. Sure, it may have been stupid of us to mis­take a few prospec­tors for an in­va­sion, but there’s no in­ter­na­tional law against be­ing stupid. If you dis­miss us as sim­ply mis­led, you don’t have to go through the trou­ble of pun­ish­ing us, and other coun­tries won’t think they can get away with any­thing.

“Nor do you need to live in fear of us do­ing some­thing like this again. We’ve already demon­strated that we won’t go to war with­out a ca­sus belli. If other coun­tries can re­frain from giv­ing us one, they have noth­ing to fear.”

Ban Ki-moon doesn’t be­lieve your story, but the coun­tries that would bear the eco­nomic brunt of the sanc­tions and regime change de­cide they be­lieve it just enough to stay un­in­volved.

The Pey­ote-Pop­ping Native

You are the gov­er­nor of a state with a large Na­tive Amer­i­can pop­u­la­tion. You have banned all mind-al­ter­ing drugs, with the hon­or­able ex­cep­tions of al­co­hol, to­bacco, caf­feine, and sev­eral oth­ers, be­cause you are a red-blooded Amer­i­can who be­lieves that they would drive teenagers to com­mit crimes.

A rep­re­sen­ta­tive of the state Na­tive pop­u­la­tion comes to you and says: “Our peo­ple have used pey­ote re­li­giously for hun­dreds of years. Dur­ing this time, we haven’t be­come ad­dicted or com­mit­ted any crimes. Please grant us a re­li­gious ex­emp­tion un­der the First Amend­ment to con­tinue prac­tic­ing our an­cient rit­u­als.” You agree.

A leader of your state’s athe­ist com­mu­nity breaks into your office via the ven­tila­tion sys­tems (be­cause se­ri­ously, how else is an athe­ist leader go­ing to get ac­cess to a state gov­er­nor?) and says: “As an athe­ist, I am offended that you grant ex­emp­tions to your anti-pey­ote law for re­li­gious rea­sons, but not for, say, recre­ational rea­sons. This is un­fair dis­crim­i­na­tion in fa­vor of re­li­gion. The same is true of laws that say Sikhs can wear tur­bans in school to show sup­port for God, but my son can’t wear a base­ball cap in school to show sup­port for the Yan­kees. Or laws that say Mus­lims can get time off state jobs to pray five times a day, but I can’t get time off my state job for a cigarette break. Or laws that say state func­tions will in­clude spe­cial kosher meals for Jews, but not spe­cial pasta meals for peo­ple who re­ally like pasta.”

You re­spond “Although my poli­cies may seem to be say­ing re­li­gion is more im­por­tant than other po­ten­tial rea­sons for break­ing a rule, one can make a non-re­li­gious case jus­tify­ing them. One im­por­tant fea­ture of ma­jor world re­li­gions is that their rit­u­als have been fixed for hun­dreds of years. Allow­ing peo­ple to break laws for re­li­gious rea­sons makes re­li­gious peo­ple very happy, but does not weaken the laws. After all, we all know the few ar­eas in which the laws of the ma­jor US re­li­gions as they are cur­rently prac­ticed con­flict with sec­u­lar law, and none of them are big deals. So the gen­eral prin­ci­ple ‘I will al­low peo­ple to break laws if it is nec­es­sary to es­tab­lished and well-known re­li­gious rit­u­als” is rel­a­tively low-risk and makes peo­ple happy with­out threat­en­ing the con­cept of law in gen­eral. But the gen­eral prin­ci­ple ‘I will al­low peo­ple to break laws for recre­ational rea­sons’ is very high risk, be­cause it’s suffi­cient jus­tifi­ca­tion for al­most any­one break­ing any law.”

“I would love to be able to serve ev­ery­one the ex­act meal they most wanted at state din­ners. But if I took your re­quest for pasta be­cause you liked pasta, I would have to fol­low the gen­eral prin­ci­ple of giv­ing ev­ery­one the meal they most like, which would be pro­hibitively ex­pen­sive. By giv­ing Jews kosher meals, I can satisfy a cer­tain par­tic­u­larly strong prefer­ence with­out be­ing forced to satisfy any­one else’s.”

The Well-Dis­guised Atheist

The next day, the athe­ist leader comes in again. This time, he is wear­ing a false mus­tache and som­brero. “I rep­re­sent the Church of Driv­ing 50 In A 30 Mile Per Hour Zone,” he says. “For our mem­bers, go­ing at least twenty miles per hour over the speed limit is con­sid­ered a sacra­ment. Please grant us a re­li­gious ex­emp­tion to traf­fic laws.”

You de­cide to play along. “How long has your re­li­gion ex­isted, and how many peo­ple do you have?” you ask.

“Not very long, and not very many peo­ple,” he re­sponds.

“I see,” you say. “In that case, you’re a cult, and not a re­li­gion at all. Sorry, we don’t deal with cults.”

“What, ex­actly, is the differ­ence be­tween a cult and a re­li­gion?”

“The differ­ence is that cults have been formed re­cently enough, and are small enough, that we are sus­pi­cious of them ex­ist­ing for the pur­pose of tak­ing ad­van­tage of the spe­cial place we give re­li­gion. Grant­ing an ex­emp­tion for your cult would challenge the cred­i­bil­ity of our pre-com­mit­ment to pun­ish peo­ple who break the law, be­cause it would mean any­one who wants to break a law could just found a cult ded­i­cated to it.”

“How can my cult be­come a real re­li­gion that de­serves le­gal benefits?”

“You’d have to be­come old enough and re­spectable enough that it be­comes im­plau­si­ble that it was cre­ated for the pur­pose of tak­ing ad­van­tage of the law.”

“That sounds like a lot of work.”

“Alter­na­tively, you could try writ­ing awful sci­ence fic­tion nov­els and hiring a ton of lawyers. I hear that also works these days.”


In all these sto­ries, the first party wants to cred­ibly pre-com­mit to a rule, but also has in­cen­tives to for­give other peo­ple’s de­vi­a­tions from the rule. The sec­ond party breaks the rules, but comes up with an ex­cuse for why its in­frac­tion should be for­given.

The first party’s re­sponse is based not only on whether the per­son’s ex­cuse is be­liev­able, not even on whether the per­son’s ex­cuse is morally valid, but on whether the ex­cuse can be ac­cepted with­out strain­ing the cred­i­bil­ity of their pre­vi­ous pre-com­mit­ment.

The gen­eral prin­ci­ple is that by ac­cept­ing an ex­cuse, a rule-maker is also com­mit­ting them­selves to ac­cept­ing all equally good ex­cuses in the fu­ture. There are some ex­cep­tions—ac­cept­ing an ex­cuse in pri­vate but mak­ing sure no one else ever knows, ac­cept­ing an ex­cuse once with the ex­press con­di­tion that you will never ac­cept any other ex­cuses—but to some de­gree these are devil’s bar­gains, as any­one who can pre­dict you will do this can take ad­van­tage of you.

Th­ese sto­ries give an idea of ex­cuses differ­ent from the one our so­ciety likes to think it uses, namely that it ac­cepts only ex­cuses that are true and that re­flect well upon the char­ac­ter of the per­son giv­ing the ex­cuse. I’m not say­ing that the com­mon idea of ex­cuses doesn’t have value—but I think the game the­ory view also has some truth to it. I also think the game the­o­retic view can be use­ful in cases where the com­mon view fails. It can in­form cases in law, in­ter­na­tional diplo­macy, and poli­tics where a tool some­what stronger than the eas­ily-mud­dled com­mon view is helpful.