martedì 30 maggio 2017

Capire il diritto: economisti contro giuristi

Ma a cosa servono i giuristi e gli esperti di diritto in genere?
filosofi studiano i principi delle leggi, gli economisti le conseguenze. Quindi i giuristi chi sono? Cosa vogliono da noi con i loro libri voluminosi? Non potrebbero cambiare mestiere e rendersi utili in altro modo?
La domanda sorge spontanea leggendo “Law and Order” di David Friedman, un economista che si occupa di diritto.
Uno legge il libro e si chiede cosa ci sia da aggiungere. Sì, magari un po’ di storia ma per il resto...
Veramente 40 anni fa la domanda era rovesciata: cosa c’entra un economista con il diritto? Ecco allora una risposta sintetica:
Someone proposes that since armed robbery is a very serious crime, armed robbers should get a life sentence. A constitutional lawyer asks whether that is consistent with the prohibition on cruel and unusual punishment. A legal philosopher asks whether it is just. An economist points out that if the punishments for armed robbery and for armed robbery plus murder are the same, the additional punishment for the murder is zero—and asks whether you really want to make it in the interest of robbers to murder their victims. That is what economics has to do with law…
Ecco, le pene sono graduate. Ma perché? Il filosofo ci dice che è GIUSTO così, e ci spiega perché; l’economista ci dice che è EFFICIENTE così, e ci spiega perché. E il giurista che ci dice? Cita qualche comma a casaccio e poi non riesco più a seguirlo, mi addormento. Mai che riesca a tenermi sveglio con qualcosa d’interessante.
Ma qui mettiamoci per un attimo gli occhiali dell’economista. Ecco chi è il delinquente per lui:
A mugger is a mugger for the same reason I am an economist: Given his tastes, opportunities, and abilities, it is the most attractive profession open to him…
Nel diritto visto dagli economisti il concetto centrale è quello di probabilità:
… It is tempting to reply that nobody should be punished unless we are certain he is guilty. But by that standard nobody would ever be punished; the strongest evidence establishes only a probabilityEven a confession is not absolute proof: While our legal system no longer permits torture, it does permit plea bargaining, and an innocent defendant may prefer a guilty plea on a minor charge to risking a long prison term on a major one…
La società deve fare una scelta di valore: quale probabilità di colpevolezza fa scattare la condanna?
… If we are to convict anyone at all, we must do it on evidence short of absolute proof. How far short? Raising the standard of proof reduces the chance of convicting an innocent defendant but increases the chance of acquitting a guilty one…
Una scelta di valore famosa è lo standard-Blackstone (90%):
If, as Blackstone wrote more than two hundred years ago, it is better that ten guilty men go free than that one innocent be convicted, we should keep raising our standard of proof as long as doing so saves one more innocent defendant…
Spesso il diritto si distingue in civile e penale proprio per dare due standard diversi. Ma perché ne occorrono due?
… law in the United States and similar systems requires a high standard of proof (“beyond a reasonable doubt”) in a criminal case but only a low standard (“preponderance of the evidence”) in a civil case. Why? The answer cannot simply be that we are more careful with criminal convictions because the penalties are bigger. A damage judgment of a million dollars, after all, is a considerably more severe punishment for most of us than a week in jail…
Il giurista glissa ma per l’economista la risposta è semplicissima: nel primo caso la pena è una compensazione tra privati, nel secondo un costo netto sociale:
… Economics suggests a simple explanation. The typical result of losing a lawsuit is a cash payment from the defendant to the plaintiff. The result of being convicted of a crime may well be imprisonment or execution. A high error rate in civil cases means that sometimes I lose a case I should have won and pay you some money and sometimes you lose a case you should have won and pay me some money. On average, the punishment itself imposes no net cost; it is simply a transfer. A high error rate in criminal cases means that sometimes I get hanged for a murder I didn’t commit and sometimes you get hanged for a murder you didn’t commit. In the criminal case, unlike the civil case, one man’s loss is not another man’s gain. Punishment is mostly net cost rather than transfer, so it makes sense to be a good deal more careful about imposing it…
Se la funzione della pena inflitta al criminale fosse la rieducazione del condannato o il risarcimento della vittima l’arringa di questo bizzarro avvocato sarebbe vincente:   
Suppose, for example, that I take advantage of a particularly good opportunity to push my rich uncle off a cliff. By extraordinary bad fortune a birdwatcher happens to have his camera pointed in my direction at just the wrong time, with the result that I am caught, tried, and convicted. During the sentencing phase of the trial my attorney points out that my crime was due to the conjunction of extraordinary temptation (he was very rich, I was very poor) and an improbably good opportunity—and I had only one rich uncle. Besides, once I have been convicted of this crime, potential future victims are unlikely to go rock climbing with me. Hence, he argues, the court should convict me and then let me go. Whatever they do, I will never kill again, and hanging or imprisoning me will not, he points out, bring my uncle back to life. The conclusion is bizarre, but the argument seems logical…
E qui spunta il giurista: la pena serve a fare giustizia! Ma la sua risposta ci suona tautologica:
… The reply many legal scholars would probably offer is that the law is concerned not only with consequences but also with justice. Letting me go may do no damage, but it is still wrong…
Anche qui l’economista ha una risposta migliore: 
… By letting me off unpunished, the court is announcing a legal rule that lowers the risk of punishment confronting other nephews faced, in the future, by similar temptations. Executing this murderer will not bring his victim back to life, but the legal rule it establishes may deter future murderers and so save those who would have been their victims… Legal rules are to be judged by the structure of incentives they establish and the consequences of people altering their behavior in response to those incentives…
Il vantaggio dell’economia è che se hai capito la funzione di una legge hai capito tutto il diritto. Lo studente di giurisprudenza che studia il Codice Civile, per capire il diritto penale deve cominciare daccapo studiando il Codice Penale.
A law student who has learned to understand tort law has the basic equipment to understand tort law. If he wants to understand criminal law, he must start over again. Economics changes that…  As you will see, once you understand property, or contract, or tort from the point of view of economics, you have done most of the work toward understanding any of the others
Per l’economista il giurista non capisce quello che studia cosicché la sua è solo mera erudizione a pappagallo.
Così come il teologo dice allo scienziato che senza dare un senso compiuto ai concetti che utilizza non ci sarà mai vera comprensione, lo stesso dice l’economista al giurista: tu rilevi un ordine, una coerenza ma che significato dai a tutto questo?
This is one explanation for the controversial nature of economics within the legal academy. On the one hand, it offers the possibility of making sense out of what legal academics do. On the other hand, it asserts that in order for legal academics to fully understand what they are doing, they must first learn economics
Inoltre, l’economia del diritto produce molte fastidiose conclusioni contro-intuitive Esempio: le leggi fatte a protezione di X danneggiano X. Il che non la rende simpatica a chi apprezza oltre misure le “buone intenzioni”.
… A second reason economic analysis is controversial is that it sometimes produces conclusions with which many legal academics disagree—for example, that laws “protecting” tenants are quite likely to make tenants worse off
Altro attrito: gli economisti sono generalmente di destra, gli studiosi del diritto di sinistra.
Ma perché l’economista è di destra? Risposta:
…  the economist’s underlying assumption that individuals are rational. While that assumption does not, as we will see, eliminate all reasons for wanting to interfere with market outcomes, it does eliminate many. And while rationality is an optimistic assumption when applied to individuals who are supposed to be acting for their own interest—buying and selling, signing contracts, getting married or divorced—it can be a pessimistic assumption when applied to people who are supposed to be acting in someone else’s interests, such as judges or legislators…
D’altro canto anche il giurista puo’ insegnare all’economista, perlomeno nella misura in cui il primo veste i panni dell’economista applicato:  Prendiamo il concetto di proprietà, l’economista lo dà per scontato ma il giurista conosce bene il casino che ci sta sotto:
… An economist can talk about someone owning a piece of land and assume that that is the end of it. A lawyer dealing with property is brought face to face with the fact that ownership of land is not a simple concept. How does my ownership of a piece of land apply to someone else who wants to fly over my land, dig a hole next to it that my house might slide into, permit his cattle to wander onto my land and eat my vegetables, erect a structure on his land that shades my swimming pool?… The more you think about them, the clearer it becomes that what you own is not a piece of land but a bundle of rights related to a piece of land….
Certo che quando un economista come Ronald Coase si è occupato di diritto civile ha rivoluzionato il settore rimpiazzando il concetto di responsabilità con quello di proprietà. Per capire, pensate solo al caso di un edificio in costruzione che fa ombra alla piscina dell’Hotel adiacente. Il giurista qui vede solo un danno perpetrato dal primo operatore verso il secondo, e quindi la necessità di un risarcimento. 
… Someone builds a new hotel in Florida that shades the swimming pool of the next hotel down the beach. The owners of the old hotel sue for damages. Conventional economic analysis holds that they should win. The new hotel imposes a cost on the old; making its builder liable forces him to include that cost—what economists call an external cost or externality—in deciding whether or not the new hotel is worth building. But, as Ronald Coase pointed out in an article that laid an important part of the foundation for the economic analysis of law, that answer is too simple. It may be true that if the builder of the new hotel is not liable he need not consider the cost he imposes by locating his building where it will shade his neighbor’s pool. But if he is liable, the neighbor at an earlier stage need not consider the cost he imposes by locating his swimming pool where a building on the adjacent lot will shade it—and thus forcing the owner of that lot to either leave it empty or build and pay damages. What we have are not costs imposed by one person on another but costs jointly produced by decisions made by both parties. Part of Coase’s solution to this problem is to restate it in terms not of external costs but of property rights… The solution suggested by Coase was not liability but trade. Define the relevant legal rules so that one of the parties has a clear right to the stream of sunlight…
Certo che se privilegi l’impostazione economicista ti ritrovi ben presto con tutti i problemi dell’utilitarismo: come misurare i valori soggettivi?
… how to add people up. If a law benefits some and hurts others, as most do, how can one decide whether the net effect is loss or gain, cost or benefit?… we are comparing effects on different people using dollars as our common unit—not dollars actually paid out or received, but dollars as a common measure of value, a way of putting all costs and benefits on the same scale…
Come misurare le preferenze in modo attendibile?
… The experiment of asking people such questions is an imaginary one not only because we don’t do it but also because, if we did, there is no reason to expect them to tell us the truth… The reason I believe heroin addicts would be willing to pay quite a lot to have heroin made legal is that I observe heroin addicts paying quite a lot to get illegal heroin. The economist’s term for that approach is “revealed preference.” Preferences are revealed by choices…
Come misurare il valore di un bene?
Mary has an apple. John wants the apple. The apple is worth fifty cents to Mary, meaning that she is indifferent between having the apple and not having the apple but having an additional fifty cents instead. The apple is worth one dollar to John. John buys the apple for seventy-five cents… The transfer was an improvement.
Questa valutazione prudenziale ci fa concludere che le norme tese a facilitare il libero scambio producono sempre un valore sociale:
… We now expand the analysis by applying Marshall’s approach not to a transaction (John buys Mary’s apple) but to a legal rule. The rule is freedom of exchange: Anyone who owns an apple is free to sell or not to sell it on any terms mutually acceptable. In our two-person world the result is efficient…
Anche se Efficienza e Giustizia non sono la stessa cosa si tratta di parenti stretti:
… Although “efficient” is not quite identical to “desirable” or “should,” it is close enough so that the answer to the question “What is efficient?” is at least relevant, although not necessarily identical, to the answer to the question “What should we do?”…
Detto questo, non si vogliono nascondere le difficoltà, ecco un caso lampante in cui efficienza e giustizia divergono:
Consider a sheriff who observes a mob about to lynch three innocent murder suspects and solves the problem by announcing (falsely) that he has proof one of them is guilty and shooting him. Judged consequentially, and assuming there was no better solution available, it seems an unambiguous improvement—by two lives…
Anche equiparare tutti i valori soggettivi puo’ essere problematico:
It assumes that when evaluating the consequence of a legal rule for a single person, the appropriate values are that person’s values as expressed in his actions, that there is no relevant difference between the value of insulin and of heroin
soldi, poi, sono una buona approssimazione della felicità?
… a gain that one person is willing to pay ten dollars to get just balances a loss that another is willing to pay ten dollars to avoid. But most of us believe that, measured by some more fundamental standard such as happiness, a dollar is worth more to some people than to others—more to poor than to rich, more to materialist than to ascetic…
Quest’ultima è una critica seria. Ecco una possibile risposta:
… Marshall’s response was that most economic issues involve costs and benefits to large and heterogeneous groups of people, so that differences in individual value for money (in the language of economics, differences in the “marginal utility of income”) were likely to average out
Ma la risposta migliore è questa:
… An alternative argument for efficient law is that, even when legal rules can be used to redistribute, there are better tools available, such as taxation
Per quanto detto finora la società razionale adotterebbe un laissez-faire generalizzato. Cosa c’è che non va in questa conclusione? Essenzialmente il fatto che non tutte le relazioni sono volontarie e non tutti gli scambi a costo zero:
… When I drive my car down the street, both the car and the gasoline were obtained by voluntary exchange. But the same is not true of the relation between me and pedestrians I might run down or the homeowners downwind who must breath my exhaust. Nor is there a voluntary relation between me and the thief who steals my hubcaps… A second assumption implicit in the argument is that transactions are costless…
Una classica relazione non volontaria è quella tra inquinato e inquinatore: nessuno dei due vuole porla in essere, entrambi la eviterebbero, se non ci fosse sarebbe meglio per tutti. 
When my steel mill produces a ton of steel, I pay my workers for the cost of their labor, I pay the mining firm for the cost of its ore, but I do not pay the people downwind for the sulfur dioxide I am putting into their air… If I can eliminate two dollars worth of pollution damage at a cost of one dollar of pollution control, it is worth doing from the standpoint of efficiency—cost one dollar, benefit two. But the cost is paid by me, and the benefit goes to the people downwind, so it is not in my interest to do it…
Che fare? Una soluzione – di solito proposta dai giuristi - è “regolamentare”, e qui il laissez-faire va a farsi benedire:
… One solution is direct regulation: some government agency such as the EPA makes rules requiring steel mills to filter their smoke, or build high smokestacks, or in various other ways reduce their pollution…
Ma si tratta di una soluzione sprecona con mille problemi, eccone uno tanto per gradire (interessi disallineati): 
… While this is an obvious solution, it has some serious problems. The first is that the EPA may not be interested in maximizing efficiency
Eccone un altro (ignoranza):
… The second problem is that, even if the EPA wants to maximize efficiency, it does not know how to do it. Figuring out what pollution control measures are or are not worth taking and how much steel ought to be produced after properly allowing for the external costs of producing it are hard problems…
A questo punto arriva l’economista che propone di sostituire le regole con una tassa “pigouviana”, la cosa ha parecchi vantaggi:
… Instead of telling the firm what it must do, the regulator simply charges the firm for its pollution. If making a ton of steel produces twenty pounds of sulfur dioxide, which does four dollars worth of damage, the firm is billed for its sulfur dioxide output at twenty cents a pound… the regulator does not have to know anything about the costs of pollution control… A second advantage is that this approach generates not only the right amount of pollution control but the right amount of steel as well. When the firm produces steel, its costs now include both the cost of controlling pollution and the cost of any pollution it fails to control…
Ma permane un grave inconveniente:
… Even if the regulators are trying to produce the efficient outcome, it may not be easy to measure the damage actually done by each additional pound of sulfur dioxide, or CO2, or whatever…
Da notare che i vari passaggi possono essere ripercorsi per qualsiasi situazione che comporti un illecito civile, alla fine i problemi illustrati nel caso dell’inquinamento si ripropongono sempre.
… the same analysis can be used to explain large parts of tort law. Instead of having the EPA impose effluent taxes, we permit the people downwind to sue the steel mill for the damage its pollution is doing to their houses, laundry, and lungs… The analysis can be applied to parking fines and speeding tickets as well. When I drive fast I am imposing a cost, in additional accident risk, on other drivers. The law forces me to take account of that cost in my actions by fining me when I am caught exceeding the speed limit…
Ora una domanda impertinente: ma perché mai noi dovremmo imporre un risarcimento per a chi procura danni a terzi? Evitando di farlo l’efficienza non ne risentirebbe e tutti i problemi di cui sopra sparirebbero.
D’altronde, in parecchi altri ambiti facciamo già così: se un tale apre un bar nella stessa via dove lavoro col mio non è tenuto a pagarmi i danni, eppure me ne procurerebbe parecchi: 
… I mentioned earlier a special sort of externality called a pecuniary externality, one that imposes no net cost, since the effects on other people cancel out…  The implication of the argument is that my neighbor ought not to be able to collect damages from me for the reduction in the price of his house. Competition should not be, and is not, a tort…
Questo ragionamento intrigante puo’ essere esteso anche ai crimini (furti)? Potremmo risparmiare sulle carceri!
Purtroppo il crimine è un’attività volontaria. Prendiamo il furto: c’è da credere che la refurtiva abbia più valore per il derubato che per il ladro altrimenti quest’ultimo avrebbe formulato un’ offerta d’acquisto. Nel caso dei danni civili questa presunzione ha poco senso: la somma del risarcimento ha lo stesso valore per entrambe le parti, quindi si puo’ evitare un trasferimento. trasferimento.
Inoltre, proprio perché i crimini sono azioni volontarie, si sopportano dei costi sia per perpetrarli. Questo è meno vero per le azioni che capitano contro la nostra volontà.
… A clever—and mischievous—reader might suggest extending the argument from competition to theft… Does it follow that, just as competition ought not to be a tort, theft ought not to be a crime?… Picking pockets is not a costless activity; it involves time, training, and a variety of risks… So far we have omitted the cost to the victims of their precautions… The general term for this phenomenon is “rent seeking.” It occurs when there is an opportunity for people to spend resources transferring wealth from others to themselves…
La “domanda impertinente” interessa molto il liberista poiché implica che l’efficienza resta intatta anche se non si interviene.
Dalla “domanda impertinente” nasce la provocatoria tesi di Ronald Coase: i diritti  iniziali possono anche essere distribuiti a casaccio, ai fini dell’efficienza conta solo che siano negoziabili e che la loro negoziazione non sia costosa, il mercato penserà ad allocarli in modo efficiente.  L’economista va quindi oltre la “tassa pigouviana”:
… The existence of externalities does not necessarily lead to an inefficient result. Pigouvian taxes do not in general lead to the efficient result. Third, and most important, the problem is not really externalities at all. It is transaction costs
Coase parte dall’idea (inconcepibile per un giurista) che non ha senso distinguere tra danneggiato e danneggiatore: anche il primo con la sua presenza danneggia il secondo impedendogli di realizzare il suo progetto.
L’ombra dell’edificio in costruzione danneggia i bagnanti della piscina così come la presenza della piscina danneggia l’edificio in costruzione: si deve partire da un’intercambiabilità dei soggetti in campo. 
… Coase’s first point is that since external costs are jointly produced by polluter and victim, a legal rule that assigns blame to one of the parties gives the right result only if that party happens to be the one who can avoid the problem at the lower…
Se l’inquinato ci tiene tanto a non essere tale basta che si compri sul mercato il diritto a non esserlo più. E’ un “risarcimento al contrario”, ai fini dell’efficienza di sistema non cambia nulla.
Se l’inquinato attribuisce all’aria pulita un valore superiore a quello che l’inquinatore attribuisce all’aria sporca la legge puo’ consentire o proibire l’inquinamento, l’esito finale non cambierà: l’inquinato comprerà dall’inquinatore il suo diritto a mantenere l’aria pulita: il mercato porta alla legge efficiente indipendentemente dalla situazione di partenza. 
… The second step in Coase’s argument is to observe that, as long as the parties can readily make and enforce contracts in their mutual interest, neither direct regulation nor a Pigouvian tax is necessary in order to get the efficient outcome. All you need is a clear definition of who has a right to do what, and the market will take care of the problem… If transaction costs are zero, if, in other words, any agreement that is in the mutual benefit of the parties concerned gets made, then any initial definition of property rights leads to an efficient outcome… We have just restated the simple argument for laissez-faire in a more sophisticated form..
Se la classe operaia voleva davvero la rivoluzione comunista poteva evitare spargimenti di sangue e comprarsela in borsa diventando proprietaria di tutte le aziende capitaliste (il monte salari, d’altronde, era più elevato della capitalizzazione di borsa).
La legge migliore è la legge che si compra. La legge migliore è quella che si forma nelle clausole di un contrato privato.
E allora perché il laissez-faire non s’impone ovunque? Il perché lo dice chiaramente il teorema di Coase: perché i costi di transazione non sono pari a zero:
… Why, if Coase is correct, do we still have pollution in Los Angeles? One possible answer is that the pollution is efficient, that the damage it does is less than the cost of preventing it. A more plausible answer is that much of the pollution is inefficient, but that the transactions necessary to eliminate it are blocked by prohibitively high transaction costs… With only one landowner there would be no problem; he would offer to pay the mill for the cost of the pollution control equipment plus a little extra to sweeten the deal. But a hundred landowners face what economists call a public good problem… With many millions of people living in southern California, it is hard to imagine any plausible way in which they could voluntarily raise the money to pay all polluters to reduce their pollution…
I costi di transazione danno ancora un ruolo alla legge dei codici, purché si proponga come unico scopo quello di abbassarli.
Coase ha lavorato proficuamente su un errore molto diffuso quando pensiamo al concetto di “danno”:
… Coase’s analysis points out fundamental mistakes in the traditional way of thinking about externalities: the failure to recognize the symmetry between “polluter” and “victim” and the failure to allow for private approaches to solving such problems… Pigouvian analysis of the problem is correct, but only under special circumstances, situations in which transaction costs are high, so that transactions between the parties can safely be ignored, and in which the agent deciding which party is to be held liable already knows who the lowest-cost avoider of the problem is. Air pollution in an urban area is an obvious example. Coase provides the more general analysis… 
Ora i tribunali hanno un criterio chiaro per giudicare le richieste di risarcimento:
… Courts could follow a policy of deciding, in each case, whether plaintiff or defendant was the lowest-cost avoider… Alternatively, courts could try to establish general rules for assigning liability, rules that usually assigned liability to the right party. One example of such a general rule is the tort defense of “coming to the nuisance.” Under this doctrine if you build your housing development next to my pig farm, I may be able to avoid liability by arguing that, because I was there first, you were the one responsible for the problem. An economic justification for the doctrine is that it is less expensive to change the location of a development, or a pig farm, before it is built than after
Possiamo vedere il teorema di Coase silenziosamente all’opera nella storia, ecco un esempio delle relazioni tra apicultori e floricultori:
… Bees graze on the flowers of various crops, so a farmer who grows crops that produce nectar benefits the beekeepers in the area. The farmer receives none of the benefit himself, so has an inefficiently low incentive to grow such crops. Since bees cannot be convinced to respect property rights or keep contracts, there would seem to be no practical way to apply Coase’s approach to the problem. We must either subsidize farmers who grow nectar-rich crops (a negative Pigouvian tax) or accept inefficiency in the joint production of crops and honey. It turns out that it isn’t true. As supporters of Coase have demonstrated, contracts between beekeepers and farmers have been common practice in the industry at least since early in this century…
Il teorema di Coase ci mette a disposizione un criterio per dare confini sensati alla proprietà e rispondere quindi a domande di questo tipo:
… Does the owner have the right to prohibit airplanes from crossing his land a mile up? How about a hundred feet? How about people extracting oil from a mile under the land? What rights does he have against neighbors whose use of their land interferes with his use of his? If he builds his recording studio next to his neighbor’s factory, who is at fault? If he has a right to silence in his recording studio, does that mean that he can forbid the factory from operating or only that he can sue to be reimbursed for his losses?..
Ecco il criterio esplicitato:
…  if right A is of most value to someone who also holds right B, they come in the same bundle. The right to decide what happens two feet above a piece of land is of most value to the person who also holds the right to use the land itself, so it is sensible to include both of them in the bundle of rights we call “ownership of land.” But the right to decide who flies a mile above a piece of land is of no special value to the owner of the land, hence there is no good reason to include it in that bundle…
Naturalmente ci sono casi più problematici di altri:
… Many rights are of substantial value to two or more parties; the right to decide whether loud noises are made over a particular piece of property, for example, is of value both to the owner of the property and to his next-door neighbors…
Ad ogni modo Coase tranquillizza il legislatore: l’essenziale non è fissare la giusta legge ma fare in modo che i diritti siano facilmente negoziabili:
…In this case the argument underlying the Coase Theorem comes into play. If we assign the right initially to the wrong person, the right person, the one to whom it is of most value, can still buy it from him. So one of the considerations in the initial definition of property rights is doing it in such a way as to minimize the transaction costs associated with fixing, via private contracts, any mistakes in the original assignment…
Coase ci dice che la proprietà – ovvero la possibilità di negoziare – è un mezzo efficiente per proteggere i diritti delle persone. Tuttavia, ammettendo che esistono dei costi di transazione, non esclude che anche la responsabilità civile (e quindi il risarcimento) possa avere un ruolo. E allora sorge spontanea una domanda:
… how to decide whether rights ought to be protected by property rules (“steal a car, go to jail”), liability rules (“dent my car, pay to fix it”), or fines…
Un caso concreto puo’ essere d’aiuto:  
… Railroad trains in the nineteenth century threw sparks; the sparks sometimes started fires in adjacent fields. Railroad companies could reduce the problem either by running fewer trains or by installing a spark arrester… Farmers could reduce the problem by leaving land near the railroad track bare or planting some crop unlikely to catch fire… Farmers have only two alternatives: wheat, which burns, and clover, which does not..
Facciamo 4 ipotesi: 
We consider four different legal rules: 1. Property right by the railroad. The railroad is free to throw sparks if it wants to… 2. Property right by the farmers. The railroad may only throw sparks if it has permission to do so from all the farmers… 3. Liability right by the farmers. The railroad is free to throw sparks but must compensate the farmers for any damage that results… 4. Liability right by the railroad. Any farmer may enjoin the railroad from throwing sparks but must then compensate the railroad for the cost of having to put on a spark arrester…
Due domande:
… The symmetry is clearer if we think of each rule as answering two questions: Who decides whether the railroad throws sparks? Who bears the costs implied by that decision?…
E quattro risposte possibili:
… There are two possible answers to each question: Railroad or farmers. Combining the possible answers gives us our four rules: 1. Railroad decides, farmers bear 2. Farmers decide, railroad bears 3. Railroad decides, railroad bears 4. Farmers decide, farmers bear…
Decisioni di comportamento e responsabilità del danno, ecco i due principali parametri.
Facciamo una quantificazione per considerare l’efficienza delle quattro soluzioni. La prima sembra efficiente.
… First suppose that the damage done by fires in wheat fields is $400, switching to clover costs $800 ($8 per farmer), and a spark arrester costs $1,000 (column a of the table). The cost of the fires is less than the cost of either way of preventing them, so the efficient outcome is A: Sparks + Wheat… That outcome occurs with no transactions necessary between the parties…
Anche in una quantificazione diversa l’efficienza è garantita.
… Next suppose we reverse the costs of clover and fires; switching to clover now costs $400, and fires do $800 worth of damage (column b). The railroad throws sparks. The farmers consider their options and switch to clover, since the savings from eliminating fires make it worth doing… we have again gotten there with no transactions between the parties and no transaction cost…
Veniamo alla terza quantificazione
… Finally, suppose the cost of a spark arrester drops to $200 The railroad is still legally free to throw sparks if it wants to. But now it is in the interest of the farmers to buy the railroad a spark arrester, since doing so will cost them less than switching to clover, which is their next best alternative…
In un caso del genere è difficile immaginare costi di transazione uguali a zero qualora ci fissiamo sull’iptesi 1:
… It is in their interest, but it may not happen. The reason is the public good problem mentioned earlier. As long as enough money is contributed to pay for the spark arrester, farmers who choose not to contribute get a free ride
Certo, ci sono alcune contromisure al problema degli opportunisti:
… There are a variety of ways in which the farmers might try to overcome such a problem. For example, they might draw up a contract by which each agrees to contribute only if all of the others do… This solution depends on our assumption that all farmers are equally at risk from sparks… but… as this example suggests, the situation provides a lot of opportunity for bargaining, bluffing, threats, and counterthreats.
Nel caso della terza quantificazione è invece molto più semplice immaginare costi di transazione pari a zero con l’ Ipotesi 2:
… Turn now to rule 2. This time it is the farmers who have the absolute property right; the railroad is permitted to throw sparks only if it has permission from every farmer. What happens? If the efficient outcome is C—No Sparks + Wheat—it happens immediately with no need for any transactions. The railroad could offer to buy the farmers’ permission, but that would cost more than a spark arrester, so it is not in the railroad’s interest to make the offer…
Ma nel caso dell’ipotesi 2 le cose non funzionano altrettanto bene con la prima e la seconda quantificazione.
… Suppose, however, that the efficient outcome is A or B—sparks, with or without a switch to clover. To get there the railroad must buy permission to throw sparks from the farmers. Such a transaction, at any price lower than the cost of a spark arrester and higher than the cost of either fires (A) or clover (B), is in the interest of both railroad and farmers. It is in their interest but, again, may not happen, this time because of a holdout problem…
Lasciamo ora da parte lo strumento della proprietà (ipotesi 1 e 2) per passare a quello della responsabilità (ipotesi 3 e 4): chi decide è anche responsabile per i danni che produce ai terzi.
La regola 3 sembra efficiente nella prima quantificazione:
… The railroad can either throw sparks and pay the farmers $400 for the resulting fires or else pay $1,000 for a spark arrester; it chooses the former option…
Bisogna sempre considerare che le regole di responsabilità comportano costi processuali:
… this time when the railroad’s sparks start fires, the farmers sue for damages. We have gotten to the efficient outcome, but with an additional cost: the litigation cost of the resulting tort suits…
Il processo implica una misurazione del danno, operazione suscettibile di errori in quanto non sono a disposizione preferenze rivelate:
… Implicit in that conclusion is an important assumption: that the court can accurately measure damages… Suppose that is not the case. The fires actually do $400 worth of damage, but the court, impressed by pictures of smoldering fields, overestimates the damages and awards $1,200 in compensation to the farmers
Il rischio di errore processuale puo’ essere aggirato con una transazione:
… The solution to this problem requires another transaction. The railroad goes to the farmers and offers to buy their liability right, to pay each of them $8 in exchange for his agreement not to sue. Just as with rule 2, the parties may be able to bargain to an efficient outcome, but to do so they must overcome a holdout problem…
Ma la regola 3 potrebbe avere qualche problema con la seconda quantificazione:
Suppose we now reverse the assumption: Clover costs $400, and fires do $800 worth of damage. B is now the efficient outcome. How do we get it?… If the court simply measures the damage from fires, the obvious tactic for the farmers is to grow wheat, suffer fires, and send the bill to the railroad… We can solve this problem by having the railroad pay the farmers to switch to clover. Here again there is a potential holdout problem, but it is reduced by the fact that the railroad can pay some farmers to switch to clover, eliminating fires in their fields and the resulting liability, and pay damages to the ones who refuse to switch…
Ma cosa sentenzierebbe una corte astuta?
.A sufficiently well-informed court, applying the same principle to precautions against a continuing problem, could refuse to award the farmers the full $800 cost of their burning wheat on the grounds that half the cost is their fault; they should have switched to clover. If the farmers do switch to clover, the sufficiently smart court will recognize that they are suffering a real cost from the sparks even though there are no visible fires and award them $400 in damages…
Potrei continuare con le combinazioni, mi chiedo però se è possibile trarre una regola generale.
Di solito, affidarsi al diritto di proprietà è la cosa migliore nel caso di valutazione problematica del danno. Facciamo il caso macroscopico del diritto a respirare:
… A real-world example is the externality that I impose every time I exhale, increasing the amount of carbon dioxide in the world and thus contributing my little bit to global warming. The cost may be real, but we are quite confident that continuing to breathe and putting up with the consequences is the least costly solution to the problem, so we give each individual a right to breathe, free of tort liability for costs that his breathing may produce…
La responsabilità civile è preferibile qualora il danno sia oggettivo (e quindi sono meno preziose le “preferenze rivelate”) e l’eventuale contrattazione sia esposta a free riding (il teorema di Coase aveva anticipato questa soluzione):
… If we know that courts can measure damages accurately and cheaply, taking into account all possible precautions, then rules 3 and 4 look very attractive… Similarly, if we believe that it is easy for the farmers to solve their public good problem, perhaps because there are not very many of them and they are all friends and neighbors, rule 1 looks attractive… It is especially attractive, relative to the alternatives, if we believe courts are costly to use and incompetent at estimating damages…
Un caso di danno oggettivo sono gli incidenti stradali: il triffario dei carrozzieri è una buona approssimazione. D’altro canto, in casi del genere, contrattare a priori sul rischio è difficile.  Non è un caso se in questo ambito si applica il sistema della responsabilità.
Un caso di danno soggetti
Un caso di danno soggettivo sono i costi psicologici . In passato abbiamo fatto il caso del ladro gentiluomo che la notte ci ruba l’auto restituendocela la mattina nelle medesime condizioni: danni materiali oggettivi zero, danni psicologici alti (mi dà fastidio pensare ad un’azione del genere). In casi del genere la protezione proprietaria è ideale: se vuoi la mia auto me la puopi chiedere. La pena ideale è quella che fa da deterrente in casi del genere, indipendentemente da quanto sia il danno subito.
Altri costi psicologici sono quelli legati all’azione di chi esercita la libertà d’espressione in modo offensivo,  anche in questo caso funziona bene la proprietà: non puoi venire a casa mia ad offendere se non ti invito io. Sei libero di dire quello che vuoi se ti affitti una sala e inviti un pubblico consenziente.
Poi ci sono i casi difficili: costi psicologici inflitti in luogo pubblico ad un soggetto indistinto. Se Odifreddi parlando alla TV di stato dà del “cretino” ai cristiani infligge un danno soggettivo ad una moltitudine indistinta di persone. Non esiste né danno oggettivo né contrattazione facile. Che fare? Anche qui si applica Coase: nel caso in cui i costi (processuali, valutativi, transazionali…) siano elevati la soluzione più pragmatica impone di lasciare le cose come stanno. E i cristiani si beccheranno l’insulto di Odifreddi.
In sintesi, non è possibile ricavare una regola univoca, solo “corti astute” e la “giurisprudenza” possono sopperire a questa lacuna. Studiosi come Richard Posner sostengono che la common law non ha fatto che “scolpire” nei secoli un diritto coasiano, ovvero efficiente.
Facciamo ora qualche caso particolare: se mi esplode la coca in mano perché è stata un po’ agitata chi sopporta le conseguenze dei danni che fa? Le leggi collocano anche quei particolari diritti legati al rischio.
Per rispondere alla domanda qui sopra partiamo dall’inizio nell’analisi del rischio: perché stipulo un’assicurazione
… There is one chance in a hundred that my house will burn down this year, costing me $100,000. I go to an insurance company to buy insurance on the house. The company agrees with my estimate of the odds and concludes that, on average, it will end up paying out $1,000 on the policy. In addition to paying out on claims, the insurance company also has to pay salaries, rent on its office, and the like, so it offers to insure my house for one year at a price of $1,100. On average I am paying out a hundred dollars more than I am getting back, so why should I buy the insurance? The answer is that a dollar is not a dollar is not a dollar. If my house burns down, I am going to be much poorer than if it doesn’t, hence dollars will be worth much more to me
Spesso il concetto di avversione al rischio si confonde con quello di utilità marginale del denaro decrescente: io non stipulo certe polizze su eventi catastrofici a certe condizioni perché sono avverso al rischio ma perché se dovessi ritrovarmi privato di tutto il valore del primo dollaro che ricevo sarà per me enormemente più elevato rispetto al valore che ha un dollaro in più nel mio stipendio attuale.
E perché l’assicurazione perché stipula la polizza:
… Why is the insurance company willing to sell it? If the stockholders of the insurance company have the same pattern of tastes as I do, less value for additional dollars the more of them they have, why are they willing to accept my risk? The answer is that transferring risk does not eliminate it, but pooling risk does. With a large number of policies most of the uncertainty averages out. The insurance company that insures a hundred thousand houses can predict with considerable confidence that it will have to pay out on about a thousand fires a year…
L’assicurazione diversifica e quindi riduce il rischio.
Cio’ non toglie che per l’assicurazione ci siano dei problemi: se mi assicura dopo potrei comportarmi in modo scapestrato (tanto non pago). 
… The problem of moral hazard does not imply that insurance should not exist, but it does imply that insurance companies should and will try to design their policies in ways that reduce the problem. One way of doing so is to specify precautions the insured must take, such as installing an adequate sprinkler system… Another is for the insurance company itself to pay for some precautions, such as inspections… A less direct approach is coinsurance. The insurance company insures the factory for only part of its value. The lower the fraction insured, the more precautions it is in the interest of the owner to take…
Ora che sappiamo come funziona il rapporto assicuratore/assicurato il legislatore puo’ immaginare un contratto tipo tra la coca cola e il consumatore qualsiasi mal fine di attribuire ogni diritto a chi lo valuta di più. Ecco un caso:
… A legal rule that makes Coca-Cola responsible if a Coke bottle blows up is, in effect, mandatory insurance; Coca-Cola is insuring its customer against that particular risk. One disadvantage is that doing so reduces your incentive to be careful not to shake warm bottles of Coke. One advantage is that it increases Coca-Cola’s incentive to improve the quality control on their bottles…
Siamo in una situazione simile a quella dei treni e dei contadini. La soluzione puo’ quindi dipende dalla quantificazione specifica delle procedure per evitare il danno e dalla possibilità delle parti di contrattare.
In alternativa, la responsabilità potrebbe essere addossata interamente alla Coca cola poiché nella posizione migliore per contrattare: per esempio apponendo un messaggio sulla bottiglia che invita ad un comportamento prudente.
Il mercato delle auto usate è particolarmente soggetto al rischio e all’ inefficienza dovuta da selezione avversa (una macchina usata in vendita ha più probabilità di essere difettosa rispetto ad una macchina usata qualsiasi). Come consigliare il venditore onesto? Saperlo è importante per creare una legge efficiente.
… Sellers with cars in good condition could solve the problem by providing guarantees—any repairs in the first year to be paid by the seller. Their willingness to offer such guarantees would demonstrate that they believe their own claims about the car’s condition. Unfortunately, while a guarantee eliminates inefficiency due to adverse selection, it creates inefficiency due to moral hazard. The buyer, knowing that someone else will pay for repairs, has an inefficiently low incentive to take good care of the car…
Purtroppo la soluzione contrattuale non esiste, bisogna affidarsi alla reputazione (con i nuovi media è più facile).
Ci sono strategie anche per il compratore:
… A friend of mine who was looking for a used car devised an ingenious way of inducing sellers to reveal their private information. Having located a car he liked, he asked the seller if he was willing, for an additional payment, to provide a one-year guarantee. The seller declined. My friend continued looking. Eventually he found a car he liked whose seller was prepared to sell him a guarantee as well as a car. He bought the car—without the guarantee. This method works only if the seller does not know about it…
La responsabilità civile e il sistema della proprietà puniscono il “colpevole” dopo che ha commesso il danno. I criteri che adottano per individuare colpevole e punizioni li abbiamo visti. Che dire invece di quelle leggi che puniscono gli innocenti, ovvero coloro che non hanno commesso alcun danno né violato alcuna proprietà? Sembrerebbero non rientrare nello schema proposto.
… One approach punishes people for doing things that increase the probability of accidents ex ante: speeding, drunk driving, failing to get their brakes inspected
Pensiamo al caso del tentato omicidio: non crea alcun danno e non viola nessuna proprietà.
… For a less obvious example of the ex post/ex ante distinction, consider the puzzle of why we punish attempted murder. I shoot at you, and the bullet goes into a tree instead. Judged ex post, based on the damage done, there should be no punishment: Both you and the tree are fine…
Il fatto è che se sparate a qualcuno nell’intento di colpirlo rischiate di colpirlo sul serio. Così come rischiate incidenti se viaggiate a 135 all’ora in autostrada.
Punire i colpevoli ha i suoi vantaggi:
… The ex post approach has one important advantage over the ex ante: By making it in the driver’s interest to avoid accidents, it exploits his private knowledge of how to do so... Ex ante punishment makes it in my interest to take those precautions that the legal system, here represented by the legislature and the traffic cop, knows I should take and can tell if I am taking. Ex post punishment makes it in my interest to take any precautions that I know I should take and can tell if I am taking… The speed limit is the same for everyone, from the race car driver to the teenager with a brand-new license, because the traffic cop has no easy way of distinguishing competent drivers from incompetent ones
Le punizioni ex post sono anche molto più facili da osservare:
… The most dangerous thing I do in my car is to pay attention to my conversations with other people… but I have never gotten a ticket for it. Ex ante punishments can be imposed only on behavior that a traffic cop can observe…
Chi è incline a punire gli innocenti di solito viene chiamato “paternalista”:
… Ex ante punishment provides incentives based on the beliefs of the people making the laws; ex post provides incentives based on the beliefs of the people the law applies to. If I believe that I can drive just fine after a shot of whiskey and two beers, the knowledge that if I have an accident terrible things will happen to me provides no special reason to avoid driving when drunk. The knowledge that if I am stopped and fail the Breathalyzer exam I will go to jail does…
Un’alternativa possibile al paternalismo è l’informazione:
… If the legislators know facts about driving—that roads are especially slippery when it has just started to rain, for example—that drivers do not know, the legislators can (and do) pass that information on to the drivers in safety ads or in the booklet that everyone reads before taking his driver’s test…
Ma la funzione principale delle punizioni ex-ante è costituita dai limiti di solvibiità del danneggiante:
… To see the real advantage of ex ante punishments, consider two alternative patterns of punishment, each of which collects the same number of dollars. Under the pure ex ante rule you end up paying two hundred dollars in speeding tickets every year, and, if you injure someone else’s person or property in an accident, there is no penalty. Under the pure ex post rule there are no speed limits, and each year you have one chance in a thousand of being in an accident and having to pay a two hundred thousand dollar fine. Unfortunately, you don’t have two hundred thousand dollars in your bank account. So the result of an accident is that you forfeit everything you own, including your house, and must spend the next five years working sixty hours a week to pay back the rest of the fine… …
La punizione ex post a volte costituisce un costo netto:
… suppose the ex post fine necessary to give you an adequate incentive to avoid accidents is ten million dollars, and there is no way you can expect ever to pay that much… The obvious answer is to switch from fines to other sorts of punishments, such as execution or imprisonment…  if it is a liability payment, it goes to the victim. But if your punishment is execution, you lose a life and nobody gains one. If your punishment is imprisonment, you lose your liberty, and the rest of us have to pay for the jail… Here the relevant cost is not simply cost to the person being punished—imposing a cost on him is the point of the punishment, after all—but net cost on everyone affected, including the person punished, the people who collect fines, and the taxpayers who pay for prisons. It is net cost to everyone that is relevant to economic efficiency… the advantage of ex ante punishment is that it can be done efficiently, using relatively small fines imposed with relatively high probability…
Il problema è che anche se noi isoliamo la norma ex-ante più efficiente, chi la proporrà? E chi applicherà? Non esiste una persona interessata a farlo.
… One problem with all such systems is that even if we know what rule is efficient, it is not obvious that it is in the interest of legislators or (pace Posner) judges to set efficient rules. That observation suggests that it might be worth looking for other ways of generating efficient legal rules—in particular, an efficient mix of ex ante and ex post…
Una soluzione possibile al problema public choice: solo punizioni ex-post con assicurazione.
… Imagine that the optimal pure ex post system imposes a fine of two hundred thousand dollars for an accident, and that that is a fine that drivers can (barely) pay, making the problem one of risk aversion rather than the need to shift to less efficient punishments. We abolish all speed limits and similar regulations, set a two hundred thousand dollar fine, and permit drivers to insure against having to pay it
L’assicurazione promulgherà il codice della strada (laddove possibile personalizzato) e a gestirà i vigili. Rispetto all’autore politico avrà interesse ad un diritto efficiente. 
… One obvious approach to reducing the risk of fire is requiring sprinklers. One obvious approach to reducing the risk of accidents is requiring speed limits… Instead of enforcing laws, they enforce contracts… Under such a system the insurance company has an incentive to calculate the optimal tradeoff between ex post and ex ante…
Abbiamo visto che le punizioni ex ante possono essere razionali, come per esempio nel caso del tentato omicidio. E che dire del caso dell’omicidio impossibile, penso a quel tale che vuole uccidere infilando spilloni nella bambolina?
… But what if I am attempting murder by a method that never works, such as sticking pins in a voodoo doll? Should that be criminal? Should we punish impossible attempts?… The legal rule we are considering is Attempts by impossible means are not punishable…
Chi infila spilloni potrebbe presto conoscere metodi più efficaci, forse è meglio dargli una calmata:
… So a policy of punishing impossible attempts tends to deter real murders, murders with poison, by people who do not know whether what they think is poison will actually work…
La domanda centrale per l’economista che si occupa del diritto è sempre la stessa: è possibile una depenalizzazione universale dei reati? Se solo il civile ha pene efficienti (senza costi netti) perché non depenalizzare tutto?
La distinzione tra penale e civile porta a realtà processuali ridondanti poco comprensibili anche all’uomo della strada. 
… O. J. Simpson was first acquitted of the crime of killing his wife and then convicted of the tort of killing his wife. In another, Michael Jackson was accused of child molestation. The civil case settled out of court, at which point the criminal case was dropped, presumably because the witnesses were no longer willing to testify … 
Perché il furto è considerato un crimine anziché una semplice infrazione? Perché esistono standard di prova diversi a seconda che l’illecito sia considerato civile o penale?
La depenalizzazione universale non è un’utopia visto che nella storia è già esistita:
… it is possible to have a functioning legal system in which all offenses are torts because the Icelanders had such a system, and it functioned for more than three centuries…
Nel penale è il PM a perseguire, nel civile è la vittima. Si dice che spesso la vittima potrebbe non avere sufficienti risorse per intraprendere questa attività. Ebbene, l’Islanda ha superato questo ostacolo:
… The victim of an offense may not have sufficient resources to prosecute it… This problem can be dealt with by making tort claims transferable, as was done in saga period Iceland. A victim with inadequate resources gives or sells his claim to someone better able to prosecute it…
E qui sorge un primo problema:
… Some offenses cause diffuse injury, so nobody has an adequate incentive to prosecute them…
Anche nel civile assistiamo però a danni diffusi, e i rimedi bene o male sono stati approntati:
… This is dealt with under current law by class actions. It could be better dealt with by making claims for torts that had not yet been litigated, including ones that had not yet occurred, transferable…
Un problema spinoso è quello degli insolventi: i danni prodotti da un crimine sono elevati, molti criminali non avrebbero comunque  mezzi per compensare la vittima la quale sarebbe disincentivata a perseguirli, in questo senso verrebbe a mancare la giusta deterrenza:
… If an offender is judgment-proof, there is no incentive for the victim to prosecute him, so prosecution must be by the state
Solo schiavitù ed espianto degli organi potrebbero far fronte a questo ostacolo:
… If convicted defendants who were unable to pay money damages could be sold into slavery or dismembered for organ transplants, fewer defendants would be judgment-proof … such unattractive outcomes would provide offenders an incentive to make sure they were able to pay…
C’è sempre l’alternativa che sia lo stato a risarcire:
… The state could pay the fines of judgment-proof offenders to the victim/prosecutors, thus providing them an incentive to prosecute, and impose criminal punishments, thus deterring offenders. Such a bounty system, analogous to a voucher system for schooling (or the GI Bill, which was a voucher system for higher education), combines private prosecution with public funding…
Dopodiché, anche senza la prospettiva di un risarcimento, esiste pur sempre un incentivo a perseguire, quello di produrre deterrenza privata
… Consider an offense for which the average return from catching and punishing an offender is negative: It costs more to catch and convict him than the fine collected. In order for prosecutors to stay in business, victims must pay enforcers to take over their claims and prosecute them. The victims are still selling their claims but at a negative price… The reason to do so is deterrence. The victim wants potential offenders to know that if they commit an offense against him they risk punishment… This works for offenses for which it is possible to make deterrence a private good, such as burglary… It does not work for offenses that sell at a negative price for which deterrence cannot be made a private good because the offender does not know enough about the victim to be deterred—anonymous victim offenses. These were the sort of offenses—highway robbery
Si noti che il meccanismo della deterrenza privata è molto più efficace nel penale che nel civile:
… while the offenses we now classify as crimes are more likely than torts to be negative price offenses, they are less likely than torts to be anonymous victim offenses. A burglar deciding which house to burgle can choose to avoid houses with notices saying that their owners have paid in advance to have burglars prosecuted. A driver cannot readily adjust his level of care to take account of which other cars have notices on them saying that their owners have paid in advance to have drivers who run into them prosecuted…
Ci sono poi obiezioni più sofisticate, come quella formulata da Richard Posner:
… for any offense there exists some optimal amount and probability of punishment. But once we set the amount of punishment in a system with private prosecution we have no way of controlling the probability… An ideal public enforcement system, on the other hand, could set probability and punishment independently, making an ideal public enforcement system superior to even an ideal private one, at least in that respect….
In soldoni: poiché la pena ottima dipende dalla probabilità di cattura, se ci sono molti procuratori (privati) calcolare questa probabilità (e quindi anche la pena) diventa impossibile.
Una possibile risposta: istituire pene variabili a seconda della vittima (in sostanza “pene probabili”).
… The solution to this problem is for the legal system to set, not the punishment if convicted, but the expected punishment: fine paid times probability of conviction…
Va sempre ricordato che anche  se il sistema depenalizzato resterebbe inefficiente, per giudicarlo non dobbiamo confrontarlo con un sistema ideale ma con quello attuale.
C’è un motivo fondamentale per cui i criminali sono spesso “insolventi” e quindi punibili solo in modo inefficiente con costi netti:
… crimes, such as burglary, are hard to detect, so the optimal probability of conviction is low, so the fine must be high… crimes are intentional, so criminals are likely to spend resources concealing them…
Domani, nel mondo delle telecamere diffuse, la caccia al criminale sarà molto più facile e soprattutto “privatizzabile”, il che favorisce l’ipotesi di una depenalizzazione universale.
C’è poi il problema delle frodi e dei falsi colpevoli, come insegna la storia di un sistema depenalizzato come quello inglese dei secoli scorsi.
… Another important issue,  is the problem of deliberately fraudulent claims. Under any system in which offenses sell at a positive price, there is an incentive to manufacture them, to frame potential defendants… The English criminal system encountered this problem in the mid–eighteenth century. Because of concern that incentives for private prosecution were too low, the Crown established substantial rewards for successful prosecution of certain offenses such as highway robbery. The result was a series of scandals in which it appeared that the convicted offender either had been entrapped into committing the offense…
Il problema delle frodi forse spiega l’assenza nel civile di un moltiplicatore del danno (ovvero di un risarcimento suppletivo che compensi la possibilità di farla franca):
…  if victims of torts are successful litigants with probability less than one, as is surely the case, the result is an expected punishment predictably less than the damage done. The obvious solution is to add in a probability multiplier, to scale up the punishment of tortfeasors who are successfully sued to compensate for the failure to punish those who are not. One explanation for the lack of such probability multipliers is that they would be an invitation to fraud. Under current law someone is never better off as a result of being a victim of a tort; even if he successfully litigates it, all he gets is an amount sufficient to make up for the damage he has suffered…
Ma cosa caratterizza un crimine?
… Crimes have a high standard of proof, require intent, are guaranteed a jury trial, have punishments often much higher than the damage done, pay fines to the state rather than the victim, and so on…
Inoltre, la  commissione di un crimine degrada moralmente il colpevole (stigma sociale).
Ci si chiede se abbia senso che tutte queste caratteristiche vadano insieme.
La risposta è incasinata e i casi ambigui fioccano. Prendiamo il caso delle multe:
… Fines are used in criminal law, but they tend to be for offenses, such as speeding or illegal parking, that have some of the other characteristics of torts…
Lo standard di prova più elevato nel penale è spiegato dalla sua inefficienza:
… The lower the cost of punishment, the lower the (net) cost of imposing it incorrectly. So it makes sense to combine less efficient punishments with a higher standard of proof…
Del resto, rendere efficiente il sistema penale lo mette a rischio frodi e barbarie (schiavitù ed espianto organi).
Anche lo stigma ha una sua spiegazione: quando le pene sono costose per la collettività e/o quando c’è rischio di insolvenza la pena dello stigma puo’ sopperire in molti modi.
Capire se sia più efficiente classificare un illecito come penale o come civile è un gran casino poiché bisogna valutare almeno tre fattori:
… Legal rules affect behavior on many margins. They affect incentives to commit offenses, incentives to prosecute them, and incentives to prevent them
Analizziamo, in un “mondo delle telecamere”, solo l’incentivo della vittima a prevenire: gli incidenti con pedoni dovrebbero essere un crimine e i furti in casa un illecito amministrativo.
Il caso dell’ investimento pedone:
… consider accidents in which a car runs into a pedestrian and only the pedestrian is injured. We may attempt to deter such accidents either with a tort rule, in which the driver of the automobile is liable to the victim for the damage done, or with a criminal rule, in which the driver pays a fine but the victim does not receive it. From the standpoint of the driver, the two rules (with the same penalty) generate the same incentive… Under the tort rule the pedestrian suffers no cost from being run into, since his damages are fully compensated by the driver. It follows that the pedestrian has no incentive to take precautions. Under the criminal rule, on the other hand, the pedestrian pays the full cost of the accident. It follows that he has the efficient incentive to take precautions to prevent it…
Furto in casa:
… Consider next burglary, still in a world of costless enforcement. The legal system sets the penalty for burglary equal to the damage done, the value of what is stolen… The textbook example is Posner’s hunter, lost and starving, who comes across a locked cabin in the woods, breaks in, feeds himself, and telephones for help…. In this world a homeowner who puts a lock on his door is wasting his own money and the burglar’s time…. The optimal level of precaution to prevent burglary is the same as the optimal level of precaution for a supermarket to take in preventing its customers from buying its vegetables: zero… Under a criminal rule, on the other hand, the criminal takes from the victim but repays the state, so the victim has an incentive to prevent the burglary… Hence, at least in the simplified world of costless enforcement and considering only the incentive of the victim to defend himself, burglary ought to be a tort…
Dall’analisi si ricavano due conclusioni. La prima:
… There is a set of offenses that are especially difficult for private enforcement to deal with: negative price offenses with anonymous victims. Such offenses provide a plausible argument against a pure tort system…
La seconda:
… The current sorting of offenses between the categories of crime and tort has at most a modest relation to what that analysis suggests would be an efficient division…