# New Light

Our legal system assumes that a defendant is innocent until proven guilty beyond a reasonable doubt. But what constitutes a reasonable doubt? Law professors Ariel Porat and Alon Harel suggest that an “aggregate probabilities principle” might help to determine whether an accused party is innocent or guilty.

Suppose we’ve decided that the evidence must indicate a probability of 95 percent guilt before we’re willing to declare a defendant guilty. Mr. Smith is accused of two separate crimes, with a 90 percent probability of guilt in each case. Under the 95 percent rule he’d be acquitted of both crimes. But Porat and Harel point out that there’s a 10 percent chance that Smith is innocent of each crime, and aggregating the probabilities gives a 0.10 × 0.10 = 0.01 chance that Smith is innocent of both — that is, there’s a 99 percent chance that he’s guilty of at least one of the offenses.

On the other hand, consider Miller, who is also accused of two different crimes. Suppose that the evidence gives a 95 percent probability that he committed each crime. Normally he’d be convicted of both offenses, but aggregating the probabilities gives a 0.95 × 0.95 = 0.9025 chance that he’s guilty of both offenses, and hence he’d be acquitted of one.

In A Mathematical Medley (2010), mathematician George Szpiro points out that this practice can produce some paradoxical outcomes. Peter and Paul are each accused of a crime, each with a 90 percent chance of being guilty. Normally both would be acquitted. But suppose that each was accused of a similar crime in the past, Peter with a 90 percent chance of guilt and Paul with a 95 percent chance. Accordingly Peter was acquitted and Paul went to prison. But historically Peter has now been accused of two crimes, with a 90 percent chance of guilt in each case; according to the reasoning above he ought to be convicted of one of the two crimes and hence ought to go to jail today. Paul has also been accused of two crimes, with a 0.95 × 0.90 = 0.855 chance that he’s guilty of both. He’s already served one prison term, so the judge ought to acquit him today.

Szpiro writes, “Thus we have the following scenario: in spite of the evidence being identical, the previously convicted Peter is acquitted, while Paul, with a clean record, is incarcerated.”

(Ariel Porat and Alon Harel, “Aggregating Probabilities Across Offences in Criminal Law,” Public Law Working Paper #204, University of Chicago, 2008; George Szpiro, A Mathematical Medley, 2010.)

# Get On With It

Here are the Boston Beaneaters and the New York Giants on opening day 1886.

Tempers must have been running high that day — pitcher Old Hoss Radbourn (back row, far left) is giving the finger to the cameraman, the first known photograph of the gesture.

# First Things First

In Languages and Their Speakers (1979), linguist Timothy Shopen shows how greetings and leave-takings can reflect a society’s cultural values. First he gives a typical American conversation in which one friend encounters another who is 15 minutes late for work:

Hello Ed!

— Hi! How are you?

Sorry, I’m in a hurry.

— Yeah, me too.

See you on Saturday.

The whole interaction lasts five seconds; it includes a greeting and a leave-taking, but there is no actual conversation between. Here’s the same interaction in the Maninka culture of West Africa:

Ah Sedou, you and the morning.

— Excellent. You and the morning.

Did you sleep in peace?

— Only peace.

Are the people of the household well?

— There is no trouble.

Are you well?

— Peace, praise Allah. Did you sleep well?

Praise Allah. You Kanté.

— Excellent. You Diarra.

Excellent.

— And the family?

I thank Allah. Is there peace?

— We are here.

— No trouble.

— Only peace. And your father?

Praise Allah. He greets you.

— Tell him I have heard it.

— He is well. And your uncle Sidi?

No trouble, Praise Allah …

Where are you going?

— I’m going to the market. And you?

My boss is waiting for me.

— O.K. then, I’ll see you later.

Yes, I’ll see you later. Greet the people of the household.

— They will hear it. Greet your father.

He will hear it.

— May your day pass well.

Amen. May the market go well.

— Amen. May we meet soon.

May that “soon” arrive in good stead.

“Time elapsed: 46 seconds,” Shopen writes. “It is more important to show respect for a friend or a kinsman than to be on time for work, and thus we have the example of Mamadou Diarra above, already fifteen minutes late for work and not hesitating to be even later in order to greet a friend in the proper manner. First things first, and there is no question for the Maninka people about what is most important.”

# In a Word

obtest
v. to call heaven to witness; to protest against

proditor
n. a traitor; a betrayer

Is a union breaking the law if it posts a giant inflatable rat outside an employer’s facility? No, it’s not, according to a 2011 decision by the National Labor Relations Board. The Sheet Metal Workers’ Union had sought to dissuade a hospital from using non-union workers by stationing a 16-foot rat near the building’s entrance. The NLRB held that the “the use of the stationary Giant Rat (i) constituted peaceful and constitutionally protectable expression, (ii) did not involve confrontational conduct that would qualify as unlawful picketing, and (iii) did not qualify as nonpicketing conduct that was otherwise unlawfully coercive.”

The “rat collosi” are multiplying (gallery). Let’s hope they don’t stage an uprising themselves someday.

# Self-Seeking

Why do we cultivate friendships? What reason do I have to be a friend to another person, that is, to care about him for his own sake? In order to make the friendship worthwhile, such a reason would have to explain how doing it makes my own life better. But that’s a problem: If I pursue the friendship in order to improve my own life, then I’m not really being a true friend, caring about my friend for his own sake.

University of Newcastle philosopher Joe Mintoff writes, “The problem is that, even though many of us think that being a true friend makes our lives better, paradoxically this thought had better not guide our pursuit of friendship, lest this mean that we are not true friends and that our lives are not made better.” Why, then, do we seek to befriend others?

(Joe Mintoff, “Could an Egoist Be a Friend?,” American Philosophical Quarterly 43:2 [April 2006], 101-118.)

# Forward!

“The difficulty of ruling over a diverse nation,” a 1578 engraving by Antwerp-based artist Pieter van der Borcht the Elder.

James A. Garfield wrote, “All free governments are managed by the combined wisdom and folly of the people.”

From the Public Domain Review.

# Podcast Episode 132: The Mad Gasser of Mattoon

In 1944, a bizarre criminal assaulted the small town of Mattoon, Illinois. Victims reported smelling a sickly sweet odor in their bedrooms before being overcome with nausea and a feeling of paralysis. In this week’s episode of the Futility Closet podcast we’ll pursue the mad gasser of Mattoon, who vanished as quickly as he had struck, leaving residents to wonder whether he had ever existed at all.

We’ll also ponder the concept of identical cousins and puzzle over a midnight stabbing.

See full show notes …

# Self-Service

A Mrs. Harris published this verse in Golden Days on Oct. 10, 1885:

He squanders recklessly his cash
In cultivating a mustache;
A shameless fop is Mr. Dude,
Vain, shallow, fond of being viewed.
‘Tis true that he is quite a swell —
A smile he has for every belle;
What time he has to spare from dress
Is taken up with foolishness —
A witless youth, whose feeble brain
Incites him oft to chew his cane.
Leave dudes alone, nor ape their ways,
Male readers of these Golden Days.

It reads so naturally that it’s surprising to find that it contains a double acrostic: Taking the fourth letter of each line spells out QUANTITATIVE, and taking the last letter spells out HEEDLESSNESS.

# Sunrise, Sunset

Is it unjust to adopt a constitution that binds both ourselves and future members of our society? We need a set of fundamental laws to regulate ourselves, but is it fair to extend that to future citizens? Shouldn’t they have the right to choose their own rules?

Thomas Jefferson thought so. In a 1789 letter to James Madison, he held that “the earth belongs in usufruct to the living”: He thought a constitution (or any law) should expire automatically when succeeding generations make up a majority of the population. “The constitution and the laws of their predecessors extinguished … in their natural course with those who gave them being,” he wrote. “This could preserve that being till it ceased to be itself, and no longer. … If it be enforced longer, it is an act of force, and not of right.”

There’s a tension here: In order for a constitution to be successful, it has to define the organization of its society and the freedoms of its citizens, and these rules need to remain in effect for at least several generations in order to produce a healthy liberal democracy. “But those born under a perpetual constitution are expected to acquiesce to the foundational norms approved by their predecessors with neither their consent nor their participation,” writes McGill University political philosopher Víctor M. Muñiz-Fraticelli. “If a constitution is discussed, negotiated, and approved by citizens who are, necessarily, contemporaries, what normatively binding force does it retain for future generations who took no part in its discussion, negotiation, or approval?”

(Víctor M. Muñiz-Fraticelli, “The Problem of a Perpetual Constitution,” in Axel Gosseries and Lukas H. Meyer, eds., Intergenerational Justice, 2009.)

# Downtime

Recreations listed in Who’s Who by eccentric Scottish MP Sir Nicholas Fairbairn:

1975: Creative
1976: Creating
1977: Bunking and debunking
1979: Upholding what’s right and demolishing what’s left
1980: Giving and forgiving
1981: The cure and eradication of British tick fever
1983: Being blunt and sharp at the same time
1984: Philanthropy and philogyny
1986: Ornitholatry
1987: Serving queens, restoring castles, debunking bishops, entertaining knights, befriending pawns
1988: Snookering the reds and all other proctalgias
1989: Draining brains and scanning bodies
1990: Growling, prowling, scowling and owling
1991: Loving beauty and beautifying love
1993: Drawing ships, making quips, confounding Whigs and scuttling drips
1995: Languishing and sandwiching

In 1973 he listed his recreations as “Making love, ends meet and people laugh.” He said, “I think most people, if they were honest, will admit that those were their main recreations — apart, perhaps, from Ted Heath, who would probably miss out on the first and third.”

(from Neil Hamilton, Great Political Eccentrics, 1999.)