search and seizure Archives - The Prindle Institute for Ethics

July 1, 2025July 1, 2025

The Skeptical Foundations of Social Trust

In a recent column, Tim Hsiao argues that we should endorse the “presumptive reliability” of police because:

Social trust is the foundation of everyday life. We trust that people mean what they say in contracts, that businesses honor transactions, that doctors give honest diagnoses, and that countless routine interactions are based on good faith. Without this basic presumption, voluntary exchange collapses, institutions grind to a halt, and every interaction becomes a negotiation over proof.

As a lawyer, I could only smile reading these words, because I practice in precisely those areas — commercial litigation and medical malpractice. In a sense, Hsiao is right: in everyday life, we routinely presume that others will act in good faith — sort of. But particularly in areas like contracts, business transactions, and other interactions with strangers, that “trust” is undergirded by three things: (1) our awareness that should others act in bad faith, we have a remedy — specifically, a legal remedy; (2) others’ awareness that we have that remedy; and (3) our awareness of (2). Our trust in others, particularly strangers, is possible only because we know that the law makes the cost of bad faith prohibitive. And of course, in reality we know that people sometimes cheat anyway, so we often are wary of entering into contracts and other transactions. Companies spend billions in lawyers’ fees and other costs vetting their prospective agreements and the people on the other side of the table.

Social trust is only possible if underwritten by the iron rules of law — the dictates of the state, backed by the threat of force. In addition, the existence of the law itself expresses an immutable skepticism about our own fellow citizens’ honesty and integrity. To see why, imagine instituting a rule requiring your partner to pay a $1500 fine for infidelity. Surely, such a rule does not bespeak trust in one’s significant other. Rules of law are deterrents to bad action, so the imposition of law implies a sense that bad action is afoot.

There is a tradition of thought that contrasts social trust and law. It is easy to see why: the law is not expressive of trust. But as I suggested above, the law enables social trust by assuring us in our everyday interactions that others can usually be trusted. This is true even in Hsiao’s case of the rule giving presumptive credibility to police testimony regarding the existence of probable cause. The only reason the law extends this presumptive credibility to the officer is because a police department is (or should be) a highly regulated organization. Those legal and regulatory safeguards are all supposed to ensure that a police officer’s testimony will generally be reliable—because the officer is well-trained pursuant to regulations, because the officer is subject to reviews and disciplinary procedures, because the officer, in the end, is not above the law. Again, the fruit of skepticism is trust.

This line of reasoning also shows why the rule giving presumptive credibility to a 9-11 caller is very different from the one giving presumptive credibility to a police officer’s testimony regarding probable cause, even if both are reasonable. We extend presumptive credibility to a 9-11 caller because we want the police to err on the side of over-responsiveness to citizens’ distress calls. That is the policy rationale underlying the rule. There is, by the way, a law against giving a false report to the police, which could include a fake 9-11 call. That legal threat is another guarantor of credibility. By contrast, we give presumptive credibility to a police officer’s testimony because police officers are (or should be) members of a highly-regulated government agency, and the many procedural safeguards in place to regulate their conduct are supposed to ensure that they are conducting themselves in good faith. That, plus the necessity of relying upon police officer testimony to effectively enforce the criminal law, may justify the rule of presumptive credibility. Thus, Hsiao may be mistaken in thinking that logical consistency demands that we extend presumptive credibility in both cases or none, because the underlying policy rationales in these cases are very different.

The rule of law is thus the rule of a skeptic. Yet, while skeptical about our own fellow citizens’ honesty and integrity, the law is the midwife of social trust — if instituted legitimately and administered justly. That is a big “if.”

Here again, though, skepticism is part of the answer. We don’t trust our officials enough not to jealously guard the power to throw them out of office should they cross us — not in a democracy. The power of the vote implies a suspicion of power. Thus, the skepticism of the voters is, in theory, the ultimate guarantor of a well-functioning democracy. Another mechanism common to many liberal democracies is a scheme of divided powers. Again, such a scheme is premised on the expectation that people with power will try to abuse it.

Where Hsiao sees a threat to social functioning if skepticism run rampant, I see that the most successful societies in the world are also the most law-bound. A law-bound society is not one that takes its members’ good faith for granted. It is one that provides remedies for their bad faith — remedies that inflict significant pain on the wrongdoers. The relatively just, impartial administration of those remedies underwrites social trust. I also see that the most successful societies are liberal democracies, whose electoral mechanisms and schemes of divided powers are premised on the expectation of abuses of power. In short, social trust flourishes in societies under the rule of law because the law keeps people honest.

June 30, 2025

Police Officers, Vehicle Searches, and the Foundations of Public Trust

Under the Carroll doctrine (sometimes called the “motor vehicle exception”), police may search a motor vehicle without a warrant if they have probable cause to believe it contains contraband. This rule, first established by the Supreme Court in Carroll v. United States (1925), stems from the fact that vehicles are mobile and evidence inside could easily be moved or destroyed before a warrant can be obtained. Thus, if an officer has a reasonable belief that illegal items are inside a vehicle, he can search it without needing a warrant or the driver’s consent.

For the Carroll doctrine to apply, mere suspicion is not enough. There must be some objective basis for believing that illegal items are actually present. One way in which this requirement can be met is by sensory verification: if an officer sees or smells (say) marijuana or another illegal item, that sensory observation can provide the factual basis needed to justify a vehicle search. The use of odor as a basis for generating probable cause has been affirmed by the Supreme Court in United States v. Johns.

However, it would seem that such a practice is ripe for abuse. An officer can simply claim to “smell” marijuana (or any other kind of contraband) without any way to verify or falsify the observation at the scene. It is simply the officer’s word versus the occupant(s) of the vehicle. This would seem to allow officers to use odor as an excuse to conduct searches they otherwise could not legally justify. Thus, some argue that an officer’s word alone should not be trusted in these situations, given the risk of dishonesty.

The Double Standard Toward Police

The problem with this approach is that it ignores how we routinely handle sensory evidence in other contexts. Police often rely on third-party reports from 911 callers, victims, and witnesses. In many cases, these reports are the only information officers have to act on. We treat such reports as presumptively reliable for investigative purposes, and rightly so, because officers must often act quickly on limited information to protect public safety. Even though some reports may later prove to be exaggerated, mistaken, or dishonest, the system allows officers to respond based on the information they receive and then take appropriate steps to verify or discredit the report as more facts become available.

Consistency demands that officer observations deserve at least the same presumption. When an officer reports seeing, hearing, or smelling evidence of a crime, he is making a real-time judgment based on training and immediate sensory input. Like responding to reports of danger or suspicious activity, these observations often require quick decisions in dynamic and uncertain situations. Without this initial trust, officers would be forced to hesitate in circumstances where delay could compromise safety.

If anything, the case for presumptive reliability is even stronger when it comes to officers. Unlike anonymous 911 callers or civilian witnesses, officers are trained to make careful observations, are legally obligated to document their actions, and face disciplinary, civil, and criminal consequences for false reporting. Their observations are recorded in reports and increasingly subject to review through body-worn cameras and dashcam footage. While these measures are not absolute guarantees of veracity, they do provide additional layers of accountability that do not exist for most civilian reports.

Any argument against presumptively relying on police sensory observations would apply equally to eyewitness or victim reports. Both involve individuals reporting what they perceived through their senses, often without any immediate means of independent verification. If we reject the officer’s report of what he saw, heard, or smelled because of the possibility of dishonesty, we would have to reject similar reports from victims and witnesses for the same reason.

The Problem of Unfalsifiability

But perhaps the concern is not simply that officers might lie, but that many sensory claims cannot be meaningfully tested at the time of the search. Unlike physical evidence that can be inspected or recorded, an officer’s report of detecting an odor is inherently subjective and leaves no trace that can later be verified. This unfalsifiability is what fuels the worry that odor claims give officers unchecked discretion.

Yet unfalsifiability is not unique to odor. Once again, the same problem arises any time police act on eyewitness accounts, 911 calls, or victim reports. When a caller reports hearing gunshots, smelling smoke, or seeing a knife brandished, those claims are equally unfalsifiable.

How so? In most cases, there is no immediate way to directly verify whether the caller actually perceived what they claimed. The event may have already passed, no physical evidence may exist, and no recording may be available. Even if later investigation shows the event did not occur, the inherent subjectivity of perception makes it difficult to disprove that the reporting party sincerely believed what they reported at the time. After all, a person can sincerely perceive something that does not actually exist, just as a mirage appears real to the one experiencing it even though nothing is actually there.

Despite the subjectivity of experience, the legal system rightly permits officers to reasonably rely on such reports. What matters is not whether the observation can be immediately confirmed or definitively falsified, but whether the person making the report is presumed to be acting in good faith, subject to later scrutiny if necessary. This is the only workable standard for real-time decision-making, and the same presumption should apply to officer sensory observations just as it does to civilian reports.

When the Presumption Fails

Of course, presumptive reliability is not absolute. There are situations where it no longer holds, both for civilians and for officers. A habitual 911 caller known for fabricating reports, or a witness with a proven history of dishonesty, may not be treated as credible.

The same applies to officers whose past misconduct has compromised their integrity. Under Brady v. Maryland and Giglio v. United States, prosecutors are required to disclose credibility issues that bear on an officer’s trustworthiness, and testimony from such officers may carry diminished weight or be excluded altogether. In both cases, the legal system allows reliability to be rebutted when there is concrete reason to doubt the truthfulness of the report.

The Broader Question of Trust

The deeper issue is not the reliability of sensory evidence but the public’s selective skepticism toward police officers. Those who reject presumptive reliability for police often assume that officers, by virtue of their role, are especially prone to dishonesty or abuse. If that assumption were consistently applied, it would call into question nearly every discretionary decision officers make. Policing cannot function if officers are categorically distrusted whenever they report observations that form the basis of enforcement action.

But maybe that’s exactly what some people want. The push to reflexively distrust police often comes from the same movements that seek to undermine confidence in public institutions more broadly. Yet this skepticism, if applied consistently, threatens more than law enforcement.

Of course, some level of distrust is justified. There are bad actors, and there are times when claims must be questioned. But constant suspicion applied across the board leaves no room for cooperation. A society that defaults to assuming dishonesty from everyone creates a climate where people second-guess motives and treat each interaction as involving potential deception. Over time, that kind of environment breeds widespread paranoia and makes ordinary functioning almost impossible.

This is why presumptive reliability matters. Police officers, like everyone else, should be presumed to report their observations truthfully unless there is good reason to believe otherwise. The alternative is not more accountability, but paralysis in law enforcement and in society as a whole.

September 10, 2019December 14, 2022

Faulty Forensics: Justice, Knowledge, and Bias

image of police tape with police lights in background

In June, Netflix began releasing a series called “Exhibit A,” which debunks one form of crime investigative science per episode. Dubious forensic techniques have been exposed for decades, yet still have been successful in incarcerating countless people. There are a number of reasons that this should be troubling to all of us and motivate real change. One issue that highlights the severity of continuing to rely on debunked forensic techniques is what psychologists call the “CSI effect” – jurors place an over-valued amount of credulity on evidence based on forensic methods. Thus, in a trial scenario, it is not just that some evidence is not as reliable as it seems, but it is just this sort of evidence that jurors seem to cling to in making their decisions.

It is well-documented that, even in some circumstances that we believe ourselves to be working with logical facts, we can be swayed by socialized prejudices and biases about historically disenfranchised, stigmatized, and marginalized groups. This is obviously unfortunate because it can lead to the continued unjust circumstances and treatment of such groups. A great deal of policies in a criminal justice system are put in place in order to create a more objective and just system than would be attained were the suspicions and individual reasoning of particular people with a great deal of power given full reign over crime and punishment. Practices in trials, standards for evidence, protections of citizen’s rights, and other features in the criminal justice system are in place to correct for the ways that injustices are socialized into individual reasoning, and improvements have been attempted to combat implicit biases in individual policing in many districts as well.

Because humans are socialized with these heuristics in our reasoning that are influenced by stigma and prejudices, people in the criminal justice system rely on the science of forensics to be more objective than hunches, suspicions, and our sometimes unreliable reasoning. These tools are one method of separating the functioning of our justice system from the injustice of our society. However, doubt has been cast on a number of common methods of forensics and the reliability of these tools.

Ten years ago, a report by the National Academy of Sciences stated, “[w]ith the exception of nuclear DNA analysis, . . . no forensic method has been rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source.” Blood splatter analysis, bite mark analysis, fingerprint analysis, and, perhaps most well-known to be unreliable, lie detector tests, all have had scientists’ doubt cast on them. The continued use of these methods in the court of law stacks the deck against defendants. Practitioners of the forensic methods “often believed their methods were reliable and their conclusions were accurate with little or no scientific foundation for their beliefs. As a consequence, judges and jurors were misled about the efficacy of forensic evidence, which too often resulted in wrongful convictions.”

Years ago, a study found that drug-sniffing dogs reacted to clues from the beliefs of their handlers. In the last two years there have been some efforts to develop training to minimize this bias. This is crucial for the system, for the drug-sniffing dogs are meant to be an objective way of detecting substances for further investigation, and, in most states, an alert form such a dog warrants police forces to further investigate citizens. If the canines are influenced by their perception of what their handlers think, then they are not a distinct source of information regarding whether potential illegal activity is taking place. If this is the case, the dogs’ actions should not be providing legal permission to search citizens beyond the officer’s suspicion: if the suspicion alone does not warrant search, then the dog’s behavior does not warrant search.

The problem with these methods isn’t that they aren’t completely objective or reliable, it is that they are currently playing a role in our criminal justice system that outstrips how objective or reliable they, in fact, are. When they are playing such a role in a system that so significantly alters lives, and does so at a disproportionate rate for groups that are marginalized already, it is crucial to critically engage with them as tools for legitimate investigation and trail.