Similarity and Fuzziness - and More

On the nature of and grounds for the relationship between fuzziness and similarity, see John F. Sowa What Is the Source of Fuzziness?
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What Does "Relevant" Mean?

U.S. legal scholars - esp. students of the U.S. law of evidence - have wrestled for decades with the potentially unlimited reach of the (supposed) constraint on the admissibility of evidence known as "relevance." See, e.g., 1 & 1A Wigmore on Evidence Sections 12, 28 & 37.4 (P. Tillers rev. 1983). Decision makers in the national surveillance state have capitalized on the amorphousness of "relevance" to authorize government collection of vast amounts of data. See Debra Cassens White Surveillance court redefined ‘relevant’ and special-needs doctrine to permit broad data collection ABA Journal (July 8, 2013).

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Type 1 and Type 2 Cognitive Processes and the Supposed Relationship between These Two Supposedly Distinct Processes

My intuition and some reasoning (see, e.g., part III of my essay Are There Universal Principles or Forms of Evidential Inference?) lead me to suspect that this comment by T.J. Henkle about Type 1 and Type 2 cognitive processes is largely on target.

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Saturn

Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
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Trial Use of Videos of Police Interviews of Rape Victims

Jane Lee, Criminal Law Review study backs video evidence in rape trials Sydney Morning Herald (November 11, 2013):

"Adult victims of childhood abuse should be able to give evidence against their alleged perpetrators using video-recorded interviews with police in criminal trials, researchers say.

"A study of adult rape victims in New Zealand has found that more than two-thirds of the details they revealed in their initial interviews with police were later left out when they testified as witnesses in court during criminal trials.

"The study, published in the Criminal Law Review journal, said that video-recorded evidence allowed witnesses' memory to be treated 'more like a "crime scene" by examining and preserving memory in a forensically safe way so that the courts receive the best evidence as measured by accuracy and completeness'.

"One of the study's authors, Dr Nina Westera, said that police used special techniques to jog a person's memory of an event and to recall it in narrative form over a longer period of time. By contrast, criminal trials often occurred years after the alleged crimes and witnesses were interviewed more quickly in a more formal, stressful environment.

"Child victims had been able to use such videos as their evidence-in-chief since the 1980s. In recent years, New Zealand, England, Wales and Norway had extended this to adult victims, who were then asked extra questions from the prosecution and cross-examined by defence lawyers.

"But in Australia, videos of police interviews could only be used as evidence for adults with intellectual disabilities."

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TWTR

I nvr wll twtr.
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The New Calculus: 320,000,000 Invasions of Privacy for 300 Leads

"'The NSA allegedly collected the phone records of 320 million people in order to identify roughly 300 people who might be a risk. It's just bad public policy…and perhaps illegal,' [Eric Schmidt of Google] said. 

... 

"'There clearly are cases where evil people exist, but you don't have to violate the privacy of every single citizen of America to find them,' he said."

Wall Street Journal Online (Nov. 4, 2013)

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Retirement Announcement

See this announcement.

   But this blog will continue (at least for the time being). &&& The dynamic evidence page

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Clearly The Dog Did Not (yet) Bark

Dennis Overbye, Dark Matter Experiment Has Detected Nothing, Researchers Say Proudly (October 30, 2013)

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Judge Richard Posner on Lawyers' and Judges' Fear and Loathing of Numbers, Technology, and Science

Jackson v. Pollion, No. 12-2682, at pp. 2-8 (7th Cir., October 28, 2013) (Posner, J.):

What is troubling about the case is not its disposition but that both the district judge, and the magistrate judge whose recommendation to grant summary judgment the district judge accepted, believed that Jackson “can present evidence permitting a reasonable inference” that he had experienced a serious medical condition as a consequence of the interruption of his medication. This is mistaken, and (not surprisingly) has no support in the record. But it is not only repeated in the plaintiff’s brief in this court, as one would expect; it is largely ignored by the defendants.

 

This lapse is worth noting because it is indicative of a widespread, and increasingly troublesome, discomfort among lawyers and judges confronted by a scientific or other technological issue. “As a general matter, lawyers and science don’t mix.” Peter Lee, “Patent Law and the Two Cultures,” 120 Yale L.J. 2, 4 (2010); see also Association for Molecular Pathology v. Myriad Genetics, Inc., 133 S. Ct. 2107, 2120(2013) (Scalia, J., concurring in part and concurring in the judgment) (“I join the judgment of the Court, and all of its opinion except Part I–A and some portions of the rest of the opinion going into fine details of molecular biology. I am unable to affirm those details on my own knowledge or even my own belief”); Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 599 (1993) (Rehnquist, C.J., concurring in part and dissenting in part) (“the various briefs filed in this case … deal with definitions of scientific knowledge, scientific method, scientific validity, and peer review—in short, matters far afield from the expertise of judges”); Marconi Wireless Telegraph Co. of America v. United States, 320 U.S. 1, 60–61 (1943) (Frankfurter, J., dissenting in part) (“it is an old observation that the training of Anglo‐American judges ill fits them to discharge the duties cast upon them by patent legis‐lation”); Parke‐Davis & Co. v. H.K. Mulford Co., 189 F. 95, 115 (S.D.N.Y. 1911) (Hand, J.) (“I cannot stop without calling attention to the extraordinary condition of the law which makes it possible for a man without any knowledge of even the rudiments of chemistry to pass upon such questions as these. … How long we shall continue to blunder along with‐out the aid of unpartisan and authoritative scientific assistance in the administration of justice, no one knows; but all fair persons not conventionalized by provincial legal habits of mind ought, I should think, unite to effect some such advance”); Henry J. Friendly, Federal Jurisdiction: A General View 157 (1973) (“I am unable to perceive why we should not insist on the same level of scientific understanding on the patent bench that clients demand of the patent bar, or why lack of such understanding by the judge should be deemed a precious asset”); David L. Faigman, Legal Alchemy: The Use and Misuse of Science in Law xi (1999) (“the average lawyer is not merely ignorant of science, he or she has an affirmative aversion to it”).

The discomfort of the legal profession, including the judiciary, with science and technology is not a new phenomenon. Innumerable are the lawyers who explain that they picked law over a technical field because they have a “math block”—“law students as a group, seem peculiarly averse to math and science.” David L. Faigman, et al., Modern Scientific Evidence: Standards, Statistics, and Research Methods v (2008 student ed.). But it’s increasingly concerning, because of the extraordinary rate of scientific and other technological advances that figure increasingly in litigation.

In 2007 the plaintiff, who was then 22 years old and serv‐ing a 40‐year sentence for first‐degree murder, was diag‐nosed with hypertension. The drugs hydrochlorothiazide (25 mg—a low dose) and amlodipine (5 mg—a normal dose) were prescribed. Later verapamil (180 mg) was substituted for the amlodipine. (Those two drugs are calcium channel blockers; hydrochlorothiazide is a diuretic.) The plaintiff claims not to have been given the drugs for a three‐week period beginning on February 15, 2009 (we’ll assume for purposes of this appeal that this is true), and that as a result he suffered loss of vision, nose bleeds, headaches, and light‐headedness upon standing up (actually a symptom of low blood pressure, see Cleveland Clinic, “Orthostatic Hypotension,"

http://my.clevelandclinic.org/disorders/orthostatic_hypotension/hic_orthostatic_hypotension.aspx (all websites cited in this opinion were visited on Oct. 18, 2013).

  

The plaintiff’s blood pressure had been taken on February 9, six days before his medication was interrupted. The reading on that occasion was 112/82 (the top number is the systolic pressure, the lower the diastolic). His blood pressure was taken next on March 9, at the end of the period of interruption, and was 142/78. “Ideal” blood pressure is considered to be below 120/80, but the top of the normal range is 140/90. The systolic pressure was thus slightly above the normal range. A single reading has little significance, be‐cause blood pressure fluctuates even when the patient is taking his medication. A week after the plaintiff resumed his medication, his blood pressure was taken again, and this time it was 114/72.

 

Unless our plaintiff has some serious medical condition unmentioned in the briefs or record, the slight elevation above the normal range that he may have experienced dur‐ing a three‐week period (we cannot say, on the basis of a single reading, that he did experience it) would not have produced the symptoms of which he complains or have en‐dangered his long‐term health. “The prolonged elevation of either the systolic or the diastolic blood pressure causes damage. If mildly elevated over a long period of time, or if highly elevated over a short period of time, damage results to a variety of different ‘target’ organs in the body, primarily due to arterial injury.” 2 Dan J. Tennenhouse, Attorneys Medical Deskbook § 24:4 (4th ed. 2012) (emphasis added); see also Norman M. Kaplan, Clinical Hypertension 124–25 (9th ed. 2006); Cleveland Clinic, “Pulmonary Hypertension: Causes, Symptoms, Diagnosis, Treatment,”

http://my.clevelandclinic.org/disorders/pulmonary_hypertension/hic_pulmonary_hypertension_causes_symptoms_diagnosis_treatment.aspx. The plaintiff experienced not highly elevated blood pressure for a short time or mildly elevated blood pressure for a long time, but mildly elevated blood pressure for a short time.

Hypertension is a serious condition. Untreated it can result in strokes or heart attacks. But a slight elevation above the normal range in an otherwise healthy young person (like the plaintiff) for three weeks will not bring on a stroke or heart attack or even materially increase the risk of a stroke or heart attack forty or fifty years later.

 

The deposition of the physician who took the plaintiff’s blood pressure on March 9 does not help the plaintiff’s case. Regarding the March 9 reading of 142/78, she said (consistent with the medical literature that we’ve cited): “I cannot say it’s a very serious, you know, condition, but it is a condition where the patient needs to take his medications.” The record refers to readings of 146/90 on two occasions in May. Although these readings were higher than the March 9 reading, the physician said that the plaintiff “would not have any symptoms with this kind of blood pressure. Seldom do you see patients with symptoms with this kind of blood pressure.”

Upon this very thin basis—the district court record con‐tains not a single reference to medical literature—the plain‐tiff’s lawyer (who acknowledged at oral argument that he had not himself conducted any research into hypertension, and whose brief contains no references to any medical litera‐ture) builds an edifice of alarm. He says that his client “be‐gan to suffer bloody noses, loss of vision and visual disturbances, and further could have suffered even more severe ailments such as stroke or even death.” The proposition that his client’s not taking his blood pressure medicine for three weeks might have killed him has no medical support in the record or the medical literature.

The magistrate judge thought the plaintiff could in a trial have presented evidence permitting “a reasonable inference that [the plaintiff’s] need for medication between February 27 [we don’t understand the choice of that date rather than February 15] and March 6, 2009, was objectively serious.” The district judge agreed that the plaintiff “suffered from an objectively serious medical condition.” These observations are irrelevancies. Hypertension is a serious medical condition because of the long‐term damage that it can do. But the issue in this case is whether the withholding of treatment during a brief period in the early stages of the condition in an otherwise healthy man in his mid‐twenties was likely to cause serious, or indeed any, harm. The disconnect between the underlying condition and the interruption in medication is underscored by the fact noted earlier that in May, two months after the interruption had ended, the plaintiff’s blood pressure was higher than it had been during the interruption.

Like the lawyers, the two judges made no reference to any medical literature. They could have skipped all medical questions, relying entirely on the lack of evidence of deliberate indifference by either defendant. But if they were going to venture an opinion on the “objective seriousness” of the plaintiff’s “medical condition,” they had to get the condition right—which was not hypertension but the medical consequences, in fact negligible, of a three‐week deprivation of medicine for mild, early‐stage hypertension. No matter how serious a medical condition is, the sufferer from it cannot prove tortious misconduct (including misconduct constituting a constitutional tort) as a result of failure to treat the condition without providing evidence that the failure caused injury or a serious risk of injury. For there is no tort—common law, statutory, or constitutional—without an injury, actual or at least probabilistic. Rozenfeld v. Medical Protec‐tive Co., 73 F.3d 154, 155–56 (7th Cir. 1996); Buckley v. Fitz‐simmons, 20 F.3d 789, 796 (7th Cir. 1994); cf. Codd v. Velger, 429 U.S. 624 (1977) (per curiam). (“A probabilistic harm, if nontrivial, can support standing.” Walters v. Edgar, 163 F.3d 430, 434 (7th Cir. 1998), and cases cited there.) As explained in Williams v. Liefer, 491 F.3d 710, 714–15 (7th Cir. 2007), “In cases where prison officials delayed rather than denied medical assistance to an inmate, courts have required the plain‐tiff to offer ‘verifying medical evidence’ that the delay (rather than the inmate’s underlying condition) caused some degree of harm. That is, a plaintiff must offer medical evidence that tends to confirm or corroborate a claim that the delay was detrimental” (citations omitted).

To determine the effect on the plaintiff’s health of a temporary interruption in his medication, the lawyers in the first instance, and if they did their job the judges in the second instance, would have had to make some investment in learning about the condition. That could have taken the form of a judge’s appointing a neutral expert under Fed. R. Evid. 706, or insisting that the plaintiff’s lawyer obtain an expert’s affidavit, or just consulting a reputable medical treatise. The legal profession must get over its fear and loathing of science.

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To which I say, "Amen, Brother." 

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Tim van Gelder: AI as - or versus - Human Intelligence Amplification

A vast amount (of hokum) has been written about artificial intelligence, but not enough has been written about artificial intelligence as a tool, about the the use of artificial intelligence - or, more simply, computer technology - to amplify, or expand, "ordinary" human intelligence. Tim van Gelder is a refreshing counterexample: this guru emphasizes, not "autonomous" AI (or computational intelligence), but "intelligence amplification" through computer technology. See Adam Ford & Tim van Gelder, Into the Deep Blue Yonder - Artificial Intelligence and Intelligence Amplification (October 22, 2013)

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Factfinding in Appellate Decisionmaking

John Schwartz, Judge in Landmark Case [Richard Posner] Disavows Support for Voter ID, NYTimes (October 15, 2013):

It is the kind of thought that rarely passes the lips of a member of the federal judiciary: I was wrong.

But there was Richard A. Posner, one of the most distinguished judges in the land and a member of the United States Court of Appeals for the Seventh Circuit, saying he was mistaken in one of the most contentious issues in American politics and jurisprudence: laws that require people to show identification before they can vote.

Proponents of voter identification laws, who tend to be Republican, say the measures are necessary to prevent fraud at the polls. Opponents, who tend to be Democrats, assert that the amount of fraud at polling places is tiny, and that the burdens of the laws are enough to suppress voting, especially among poor and minority Americans.

One of the landmark cases in which such requirements were affirmed, Crawford v. Marion County Election Board, was decided at the Seventh Circuit in an opinion written by Judge Posner in 2007 and upheld by the Supreme Court in 2008.

[snip, snip]

In a telephone interview on Tuesday, Judge Posner noted that the primary opinion in the 2008 Supreme Court decision upholding the law had been written by Justice John Paul Stevens, “who is, of course, very liberal.” The outcome of the case goes to show, he said, that oftentimes, “judges aren’t given the facts that they need to make a sound decision.” [emphasis added]

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Evidence marshaling software MarshalPlan

MarshalPlan 6.x (evidence marshaling software)

A. Background

Years ago David A. Schum and I developed the notion of an evidence marshaling system. We laid out the underlying theory of this evidence marshaling system in A Theory of Preliminary Fact Investigation. We developed a kind of computer embodiment, or computer-based expression, of our idea of an evidence marshaling system. Eventually we decided to call our system "MarshalPlan."

Some of my more recent thoughts about the theoretical foundations of MarshalPlan may be found here (long blog post called "The Ramshackle -- and Logical -- Character of Explicit Human Factual Inference" (June 18, 2011)).

In the years following my seven(!)-year NSF-supported collaboration with David Schum, I continued to tinker with MarshalPlan. I did so by both modifying and adding "stacks," or files. (Each stack corresponds to an evidence marshaling strategy, or method.) The most recent iteration of the evidence marshaling software is MarshalPlan 6.x.

A few years ago I began to make MarshalPlan available via the internet. Further below in this post I lay out a relatively simple way that many of you can now use to download and run MarshalPlan 6.x.

B. Caveats

Before you download or access MarshalPlan, please consider the following important caveats:

1. The current iteration of MarshalPlan -- MarshalPlan 6.x -- is not a prototype of a working application suitable for real-time and real-world use. Far from it! However, MarshalPlan 6.x goes beyond just scratchings (text) that explain how an evidence marshaling application might work. Even so, it is not far from the truth to say that MarshalPlan is mainly an elaborate visual illustration of some of the directions that development of software for marshaling evidence in legal settings should take. But, but ... MarshalPlan 6.x is a bit more than an illustration of possible future directions for research and development. MarshalPlan as it now stands is useful for pedagogical (i.e., teaching) purposes. Moreover, MarshalPlan is creeping ever closer to being something akin to a genuine software prototype suitable for real-world and real-time use. 

2. In MarshalPlan there are only brief explanations of some of the evidence marshaling strategies found there. Other marshaling strategies, however, are described and explained more fully. For a comprehensive account of the thinking that went into MarshalPlan, please see the readings mentioned above. If you want a truly comprehensive theory-laden explanation of MarshalPlan, you will have to invite me to give a leisurely talk (preferably on a tropical island or some other attractive venue).

3. A few buttons and links may not work. If that happens, try other buttons and links. (Otherwise resort to expletives. You have my permission.) 

4. MarshalPlan 6.x is currently not set up to be linked to a database. This is an almost fatal deficiency for any possible real-world use in a context such as law practice. (But it would not be difficult for a reasonably proficient programmer to eliminate this deficiency.)

C. Instructions

Try the following method to view and play with MarshalPlan 6.x:

Go to http://tillers.net/MarshalPlan 6.x and open the subfolder "Windows" and then click on MarshalPlan 6.x.exe. 

A free open source version of the scripting language for MarshalPlan is now available (go here). It is called "LiveCode Community."

Caveat: I reserve my copyright to MarshalPlan. This means in part that you cannot distribute, lease, or use any version of MarshalPlan for profit or for commercial purposes without my express written permission.

Nota Bene: You will very probably not be able to run MarshalPlan 6.x on an Apple computer. The Apple OS probably still strips MarshalPlan of the ability to run on Apple computers. Sorry! {Take your grievance if any to the paternalistic Apple Corporation, which likes closed worlds, particularly those that it controls.} But there is a solution! Send an email message to peter@tillers.net and ask me to share a relevant DropBox folder with you. I will probably happily oblige.

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Chapel Hill and James H. Chadbourn

A friend recently reminded me of Tom Wolfe's connection with Chapel Hill, North Carolina. My friend's reminder made me think of James H. Chadbourn, who began his academic career at the University of North Carolina. Chadbourn published a book on lynching and the law in 1933. He was 33 years old at the time and a lowly assistant professor. I imagine it took much courage to publish that book. 
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A Lesson for the Confrontation Clause?

Jennifer Kingson, Rethinking the Poker Face and Plans for a Cat in Space NY Times  (Sept. 23, 2013):

Poker Arms

In a classic work by Lady Gaga, she boasts, “No, he can’t read my poker face.” But according to a paper in the journal Psychological Science, she should be more worried about her arm and hand movements, at least when playing poker. “Even though professional players may be able to regulate their facial expressions, their motor actions could betray the quality of their poker hand,” the authors wrote. In three studies, psychologists asked undergraduates to watch clips of professional poker players placing bets; it turned out that smooth and confident arm motions while pushing the chips were the surest signal of a good hand.

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FISA Court's Mechanical Fourth Amendment Jurisprudence

For a stellar (and shocking) example of mechanical Fourth Amendment jurisprudence, see this recently declassified FISA court memorandum opinion. Apart from the opinion's singularly uninspired black-letter interpretation of the Fourth Amendment (and heavy reliance on 1970s Supreme Court precedents), the opinion is striking for the paucity of discussion - less than five double-spaced pages - devoted to the question of the constitutionality of a massive program of NSA surveillance of telephony metadata. God help us all! &&& The dynamic evidence page

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Mixtures of DNA in One Person

Carol Zimmer, DNA Double Take NYTimes (Sept. 12, 2013)

Snippets:

... [S]cientists are discovering that — to a surprising degree — we contain genetic multitudes. Not long ago, researchers had thought it was rare for the cells in a single healthy person to differ genetically in a significant way. But scientists are finding that it’s quite common for an individual to have multiple genomes. Some people, for example, have groups of cells with mutations that are not found in the rest of the body. Some have genomes that came from other people.

[snip, snip]

Dr. James R. Lupski, a leading expert on the human genome at Baylor College of Medicine, wrote in a recent review in the journal Science that the existence of multiple genomes in an individual could have a tremendous impact on the practice of medicine. ...

[snip, snip]

Science’s changing view is also raising questions about how forensic scientists should use DNA evidence to identify people. ...

[snip, snip]

... In 1953, for example, a British woman donated a pint of blood. It turned out that some of her blood was Type O and some was Type A. The scientists who studied her concluded thatshe had acquired some of her blood from her twin brother in the womb, including his genomes in his blood cells.

Chimerism, as such conditions came to be known, seemed for many years to be a rarity. But “it can be commoner than we realized,” said Dr. Linda Randolph, a pediatrician at Children’s Hospital in Los Angeles who is an author of a review of chimerism published in The American Journal of Medical Genetics in July.

[snip, snip]

A century ago, geneticists discovered one way in which people might acquire new genomes. They were studying “mosaic animals,” rare creatures with oddly-colored patches of fur. The animals didn’t inherit the genes for these patches from their parents. Instead, while embryos, they acquired a mutation in a skin cell that divided to produce a colored patch.

Mosaicism, as this condition came to be known, was difficult to study in humans before the age of DNA sequencing. Scientists could only discover instances in which the mutations and the effects were big.

[snip, snip]

The latest findings make it clear that mosaicism is quite common — even in healthy cells.

[snip, snip

Medical researchers aren’t the only scientists interested in our multitudes of personal genomes. So are forensic scientists. When they attempt to identify criminals or murder victims by matching DNA, they want to avoid being misled by the variety of genomes inside a single person.

Last year, for example, forensic scientists at the Washington State Patrol Crime Laboratory Division described how a saliva sample and a sperm sample from the same suspect in a sexual assault case didn’t match.

[snip, snip]

While the risk of confusion is real, it is manageable, experts said. “This should not be much of a concern for forensics,” said Manfred Kayser, a professor of Forensic Molecular Biology at Erasmus University in Rotterdam. In the cases where mosaicism or chimerism causes confusion, forensic scientists can clear it up by other means. In the Austrian study, for example, the scientists found no marrow donor genomes in the hair of the recipients.

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Mark Tushnet

Mark Tushnet on C-Span's After Words

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Neuroscience and Lie Detection

26:46 minutes into the following video, a brief discussion of fMRI and lie detection
David Pogue's "Can Science Stop Crime?"
Alan Alda's PBS program "Brains on Trial: Determining Guilt"



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A Path to the Solution of the Conjunction Paradox?

The "conjunction paradox" has bedeviled legal theorists for years. It still does. See, e.g., Kevin M. Clermont, Death of Paradox: The Killer Logic Beneath the Standards of Proof Cornell Law Faculty Publications, Scholarship@Cornell Law: A Digital Repository (Feb 1, 2013). Some legal theorists who doubt that the standard probability calculus is a satisfactory "model" of judicial proof are particularly prone to flog their opponents with this paradox.

But what is the conjunction paradox? According to Professor Clermont, id. at 1106, Professor Charles Nesson constructed "the best-known statement of the infamous conjunction paradox." Clermont quotes (id.) Nesson thus (original article: Charles Nesson, "The Evidence or the Event? On Judicial Proof and the Acceptability of Verdicts, 98 Harvard Law Review 1357, 1385-88 (1985) footnotes omitted)):

"We purport to decide civil cases according to a more-probable-than-not standard of proof. We would expect this standard to take into account the rule of conjunction, which states that the probability of two independent events occurring together is the product of the probability of each event occurring separately. The rule of conjunction dictates that in a case comprised of two independent elements the plaintiff must prove each element to a much greater degree than 50%: only then will the plaintiff have shown that the probability that the two elements occurred together exceeds 50%. Suppose, for example, that a plaintiff must prove both causation and fault and that these two elements are independent. If the plaintiff shows that causation is 60% probable and fault is 60% probable, then he apparently would have failed to satisfy the civil standard of proof because the probability that the defendant both acted negligently and caused injury is only 36%.

      "In our legal system, however, jurors do not consider whether it is more probable than not that all elements occurred in conjunction. Judges instruct jurors to decide civil cases element by element, with each element decided on a more-probable-than-not basis. Once jurors have decided that an element is probable, they are to consider the element established, repress any remaining doubts about it, and proceed to consider the next element. If the plaintiff proves each element by a preponderance of the evidence, the jury will find in his favor.... Thus, jurors may find a defendant liable even if it is highly unlikely that he acted negligently, that is, the conjoined probability of the elements is much less than 50%. In such cases, the verdict fails to reflect a probable account of what happened and thus fails to minimize the cost of judicial errors ...

"...

"... Although courts direct juries to consider and decide each element seriatim, juries do not consider each item of evidence seriatim when deciding whether a given element is proved. The jury must decide each element by looking at all of the evidence bearing on proof of that element. Thus, although the jury does not assess the conjunction of the elements of a case, it does decide each element by assessing the conjunction of the evidence for it."

The conjunction paradox persists even if we assume juries are told to assess the probability of a whole claim (or affirmative defense) as well as the probability of each element of the claim (or affirmative defense).

The conjunction paradox persists even if we assume that there are some partial dependencies among the elements of a claim (or affirmative defense).

The conjunction paradox takes an acute form in criminal cases - in which, let us assume, jurors are instructed they must find that proof establishes each element of the charge beyond a reasonable doubt and also the entire charge beyond a reasonable doubt. The problem here is that if the charge has two or more essential elements and if a numerical value such as a .95 probability is assigned to "beyond a reasonable doubt," it seems to follow, by probability logic - specifically the product rule, contrary to the instructions jurors are actually given,  that they must find that the probability of at least one of those elements must be very substantially above .95. If not, it seems to follow - by the probability logic - that jurors can return a guilty verdict even if they believe that the probability of the existence of all the essential elements taken together is less than .95.

I have made some entirely unsatisfactory attempts to develop a solution to the conjunction paradox. See, e.g.,

Sunday, April 18, 2010

My Muddled Musings about L.J. Cohen's Conjunction Paradox

Cf. my unsuccessful attempt to begin to find another way through the muddle:

Sunday, November 21, 2010

Three Questions about the Conjunction Paradox

I am now going to try to begin work toward very different kind of solution. Consider the following (fragmentary and tentative!) gambit:

Take the following possible situation (Situation X):

At about 3:00 p.m., on June 5, 2013, (a) James Jones becomes angry at Valiant Victim, (b) decides to hurt Valiant Victim, (c) picks up a knife, and (d) stabs Valiant Victim.

We can think of the Situation X as a set of distinct events a – d .

We can also think of the above situation Situation X as one event - as a single event - that has a number of parts or features (e.g., the events or features above, a – d ).

Probability theory alone does not tell us which of these two ways we should or must think of Situation X.

If we can or should think of Situation X with features a – d (only) as a single (possible) event, we are free to think of the question of the probability of Situation X without believing that we must or should think of the probabilities of each of the events or features a – d.

• It is quite true that it is possible think of Situation X as a (possible) compound event that is nothing more than the collection of (possibly-connected) distinct events a – d over time.
• If we think of Situation X in (only) this way, we can and surely must (at the very least) think of the separate probabilties of each of the events a – d if we wish to assess the probability ofSituation X.
• Given the hypothesized way we are now thinking of Situation X, if we do not ponder these separate probabilities, we cannot possibly assess the probability of Situation X. This is because we think of Situation X as nothing more than the conjunction (over time) of events a – d.
• But it is also true that it is possible to think of Situation X(only) as a single event with the features a – d over time. In that event, if we wish to assess the probability of Situation X, the structure of our thinking (or imagination) about Situation Xdoes not force or drive us to ponder the separate probability of each a – d. Indeed, if we think of Situation X as nothing more than a single event, we cannot readily imagine the possibilty of separate assessments of the probability of each a – d.

But a question: In a trial we take (and must take) evidence about matters such as events or elements a – d. Does it follow that we must think of (factual) hypotheses such as Situation X as being nothing more than a possible composite event consisting of events a – d?

Answer: I don't think so. The evidence in question may generate in our minds the hypothesis Situation X with the features a – d. Cf. P. Tillers & D. Schum, A Theory of Preliminary Fact Investigation, 24 University of California at Davis Law Review 931 (1991) (arguing in part that evidence serves to generate and refine hypotheses as well as to prove or disprove formulated hypotheses). But once a factual hypothesis is crystallized in our minds, we are free (as a logical matter) to think or imagine that the evidence about a – d is nothing more than evidence about the entire hypothesis Situation X.

But note (and this is an important note, a very important refinement): As I have hinted above - by using words such as “only” and “just” - I think it is both possible and likely that our minds shift between thinking of a factual scenario such as Situation X as being, one the one hand, a single event and, on the other hand, a composite event (i.e., an event consisting of distinct sub-events). If this is the case, it follows that when we shift from one way of thinking about a factual scenario to the other, the way that probability theory is applied to the situation also changes and must change. And that's perfectly fine and appropriate. Probability theory is a formal tool that does not, by itself, specify or even suggest how possible events in the world should or must be carved up.

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