What is the philosophical basis for the notion that somebody is "innocent until proven guilty"?

This seems to imply that we can confidently assert that a person is innocent until proof to the contrary emerges.

But that is obviously fallacious. Rather, the statement should be "neither innocent nor guilty, until proven to be either innocent or guilty".


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    Asymmetry between individual and institutions: in order to prevent that individual liberty be canceled by "power". Mar 13 '18 at 17:53
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    See Presumption of innocence: "In sources from common law jurisdictions, the expression appears in an extended version, in its original form and then in a shortened form. As extended, it is: *Ei incumbit probatio, qui dicit, non qui negat; cum per rerum naturam factum negantis probatio nulla sit*—"The proof lies upon him who affirms, not upon him who denies; since, by the nature of things, he who denies a fact cannot produce any proof." Mar 13 '18 at 17:59
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    Possibly because false positives are more harmful than false negatives. Mar 13 '18 at 20:30
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    This is a really good question because it asks for the grounds of a notion which most of us take for granted without being able to give clear and distinct grounds for.
    – Geoffrey Thomas
    Mar 14 '18 at 9:49
  • I've never bought this phrase in the U.S. The "innocent" are treated very differently than how would treat truly innocent people: they are jailed, or require bail to stay out of jail (which is sometimes denied them or the amount is set too high to fulfill). In actual fact, they are in a kind of state of suspicion from the moment of arrest until either indictment or exoneration.
    – Chelonian
    Mar 15 '18 at 14:09

12 Answers 12


The presumption of innocence in law serves the same purpose as the null hypothesis in science. The purpose is to produce an accurate outcome in relation to the facts at hand and the seriousness of the question to be settled.

Criminal trials begin at the null hypothesis: the defendant’s actions, whatever they might have been, were not within the range of prohibited behavior. In the absence of proof, the default assumption is that the crime is randomly related to anything the defendant might have done.

The null hypothesis is fair.

The null hypothesis is rather an ingenious creation.... The utility of the null hypothesis is that the case is not prejudged-- you are not caught defending a relationship specified beforehand.

Hoover and Donovan, The Elements of Social Scientific Thinking, 6th ed. (New York: St. Martin’s Press, 1995), p. 81.

The same process appears in civil cases, where there is no corresponding presumption. Suppose the claimant wants to sue over a personal injury. The claimant must assemble enough evidence to show that the chain of events leading up to the injury was not merely an unrelated set of accidents. The evidence must show the connection between the defendant’s behavior and the injury. In short, there must be enough evidence for the jury to reject the null hypothesis: the idea that the plaintiff suffered his injuries as the result of ordinary coincidence.

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    I like the idea of connecting the notion with the null hypothesis. This angle didn't occur to me - it's a clever move.
    – Geoffrey Thomas
    Mar 14 '18 at 9:51
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    in addition, the advantage of both the null hypothesis and innocent until proven guilty is that it limits the need to prove a negative. It is notoriously hard to prove that something didn't occur than that it did. There is also the practical consideration that forcing the burden of proof on the accuser reduces the prevalence of spurious claims.
    – Alex
    Mar 16 '18 at 13:30


Under this presumption the accused is to be considered innocent until proven guilty of a criminal offence. This is usually taken to entail that that the accused must be treated as innocent until proven guilty beyond reasonable doubt of all questions that need to be answered in order to convict him or her of the offence.

'Innocent until proven guilty' is only a rule of legal procedure. At the start of proceedings a person is not necessarily believed to be innocent by anyone but is hypothetically innocent, i.e. is merely treated as innocent, until evidence is produced that in the court's judgement determines guilt or innocence. Agreed : the prosecution does not treat the accused as innocent but the court, which determines guilt or innocence, does.

The nature of reasonable doubt needs to elucidated but is not the central issue here.


The 'innocent until proven guilty' rule is sometimes regarded as a requirement of natural justice. If I knew what natural justice was, I would examine this claim. Since I don't, I won't.


It is widely assumed that the presumption of innocence rule embodies the moral principle that it is better for the guilty to go free than the innocent be convicted. This principle is best served, it is assumed, when a defendant can be convicted of a criminal offence only if it is known that s/he is guilty of that offence : his or her guilt has been proven guilty beyond reasonable doubt.


If I am accused of a crime, say a mugging, and I am innocent, I may not be able to produce evidence to prove my innocence. Say I was alone indoors at the time of the crime. The crime occurred perhaps three months ago. A witness has described someone who looks like me as the mugger. How can I prove that I was not the mugger ? Since I can be so easily disadvantaged in proving my innocence, it seems only reasonable, given the potentially serious costs and consequences of conviction to me, that the accuser should be required to prove my guilt. In many circumstances I cannot prove my innocence when I am innocent; the least that can be required of my accuser is that they produce evidence that their accusation is sound and correct.


TL;DR The phrase "innocent, until proven guilty," is a false dichotomy, as the court never tries to prove a person's innocence, only that the defendant is "not guilty." The defendant is taken to be "not guilty" until proven otherwise, and the court makes no declaration of the person's actual innocence.

Full Thought:

Another slant to take on this phrase "innocent until proven guilty" is that it is colloquial in style.

A more accurate rendering would be "not guilty until proven guilty" (but this isn't as catchy). A court (and in a greater fashion any falsifiable proposition) may not be able to proven innocent (or false), only that the person is "not guilty." (For instance, proof of an invisible teapot orbiting the sun cannot be proven false - Russell's Teapot).

On the flip side, a common methodology employed by jurors is the idea of "beyond reasonable doubt" regarding a person's guilt. Any shadow of doubt means the juror should acquit the defendant as "not guilty," which is not to say that the person is indeed "innocent," if you catch my drift.

Courts only address the concept of guilt and never make a proclamation of innocence. This is also why the prosecution must do all the proving--they have to prove the guilt. The defendant has no such duty to prove innocence.

In light of philosophy, I'm in agreement with another answer that the concept of the null hypothesis seems a better study. The legal precedent of innocence and guilt rarely finds its way into science or philosophy (IMO).


Rather, the statement should be "neither innocent nor guilty, until proven to be either innocent or guilty".

No. Either the defendant is innocent or guilty; there is no Schroedinger cat here. Either the defendant committed a crime, or s/he did not commit a crime. That we know, or that we do not know, which is the truth, is a different problem, that does not create a third, intermediate, category between guilt and innocence.

If the defendant is innocent, s/he will be acquitted; if s/he is guilty, s/he will be sentenced (to prison, to death, to a fine, etc). S/he cannot be neither imprisoned nor not imprisoned. So a decision has to be made: either the defendant must be acquitted, or the defendant must be convicted. And that within a reasonable lapse of time, for an unterminable process amounts to making the defendant suffering a penalty while not being convicted.

And so, the sentence should be read as meaning, "if the prosecution cannot demonstrate the defendant's guilty beyond reasonable doubt, then the defendant must be acquitted, as if s/he was innocent" - even if we don't know that for sure.

I would caution against the tendency of dealing with juridical problems as if they were philosophical issues. Law is not philosophy, and what may seem to be the best and most sound reasoning, philosophically speaking, may not point to the best course of action, juridically speaking.

Juridically, it is best to try to understand the consequences of law upon the way society is organised. You can easily imagine what the consequences would be of creating a third category, "neither guilty nor innocent", for the liberties and rights of common citizens: the possibility of holding people in jail while the prosecution endlessly tries new and newer hypotheses about a crime; the possibility of life long stigma upon those who cannot demonstrate perfect innocence (potentially amounting to "cruel and unusual" punishment without even due process); and, also potentially, actual criminals going unpunished because the prosecution gets stuck to lawfaring an innocent.


Because the default condition is "free and equal"

...and because "Innocent until proven guilty" is actually a bad description of the principle. The more proper phrasing would be:

Not considered guilty, until it is proven they have committed criminal acts, whereupon they are considered guilty.

Anyway, let us start from first principles...

All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.

Article 1 of the Universal Declaration of Human Rights.

Born free, equal in dignity, equal in right, act in spirit of kinship.

Now make a quick leap to the prison inmate. They are not free and equal in rights, they are incarcerated. They do not have the freedom/rights of movement, travel, work, association, expression as the rest of us. They are not equal in dignity, we have labeled them "criminal", with the humiliation and shame that follows. We are not acting upon them in kinship, instead we have — for the time being — removed them from the community and stated they may not be a part of it.

How did we get there? How did we justify ripping a person's rights and freedom away from them? As stated above we have collectively decided that we all start out as free and equal to everyone else in rights and dignity. So what makes us able to violate that?

Because we have decided that if a person commits an act that we have deemed reprehensible, we will sentence them to retribution and/or rehabilitation. We have decided that in that particular case, it is justified to deviate from the original statement.

But now enters uncertainty, the problem of knowing. There is a possible mismatch here between knowing what a person has done, and what they have actually done. There is uncertainty between how we regard a person, and what that person has actually done.

Ponder the following matrix:

  1. A person have not committed any crimes — in other word they are innocent — and we know that for sure.
  2. A person have not committed any crimes — they are innocent — but we do not know that for sure.
  3. A person have committed a crime — they are guilty — but we do not know that for sure.
  4. A person have committed a crime — they are guilty — and we know that for sure.

In the case of uncertainty, which do we find more important? To sentence the those that have committed crimes, or to avoid sentencing the innocent?

We have decided that the innocent must never suffer having their freedoms, dignity, and rights taken away from them. This is of much higher priority than sentencing the guilty.

Why have we done that? Because we can easily imagine the outrage and anger of having your freedoms ripped away from us without proper cause, we think this is unjust. We can also empathise with others that may suffer such injustices, and as such we have decided that in case of uncertainty it is more important to keep the innocent away from sentencing that it is to sentence the guilty.

Now let us return to the four points above. In points 1 and 4, the situation is clear. There is a match between what we know and what the person has done. In point 1, the person is not sentenced. In point 4, the person is sentenced. Easy.

But what about points 2 and 3? When information is lacking, we — as outside observers — cannot tell for sure if the person committed a crime or not. If we were to sentence someone at that point, we run the risk of sentencing an innocent. This — as stated above — is unacceptable; no innocents shall ever be sentenced.

So how do we transition from a state of uncertainty, to the kind of certainty that allows us to say "This person has committed a crime, and we know this"? We do this by proving that they have committed the offending acts. In other words: we prove their guilt.

Until we have done that — until we have proven that they did it and thus rightfully allowing us to consider them guilty — we consider them as if they are "not guilty". So in the case of points 2 and 3 above, we say that in order to avoid the risk of labelling people that are not guilty as guilty, we state that anyone that is not proven guilty shall not be considered guilty even if they actually are guilty.

So what about "innocent"? Well we are not really interested in that except to say that proof of innocence is also proof of no guilt. Proven innocence ends the case immediately. But this only covers point 1 of the four points above. We also need to cover points 2 and 3. The only thing that distinguishes points 1, 2 and 3, from point 4, is the knowledge — i.e. the proven claims — that they are guilty.

Hence: not considered guilty, until proven guilty, then considered guilty.


What is the philosophical basis for the notion that somebody is "innocent until proven guilty"?

The reason why the presumption of innocence should be observed is political and institutional.

The government can extract virtually unlimited money from the population in taxes. The government has an enormous armed force called the police that it can use to hunt down and persecute people, as well as search a person's possessions without his consent. The government has a vast army of officials who can spend all day every day looking for ways to prosecute anyone they happen to want to target for any reason.

The defense has some lawyers who can't use force except in self defense. Nor can they take stuff without a person's consent. The accused person will often be locked up until his trial so he can't participate much in his own defense.

So the deck is stacked against the defense, and in recognition of that fact, the prosecution is supposed to give itself a handicap - the presumption of innocence.


It is not appropriate to interpret the legal doctrine of presumption of innocence ("innocent until proven guilty") as an epistemological principle for optimal reasoning about reality under uncertainty. (For that we have probability and statistical theory.) Rather, it is a procedure adopted as a response to the lessons of history, that is regarded as avoiding undesirable consequences under certain circumstances which hold in a legal context:

  • The context of this principle occurs within judicial proceedings, where the court has to come to a decision of whether to punish someone (by force) or not. History teaches us that the use of force by an agency of the State is a big deal, and not to be taken lightly.

  • This problem facing the court necessitates setting some onus of proof and associated evidentiary threshold. Any evidentiary threshold entails some false-positives (innocent people found guilty) and some false negatives (guilty people acquitted).

  • Historical and other evidence has shown that when the punitive institutions of the State place the onus of proof on a criminal defendent, this effectively gives them broad power to punish people arbitrarily (since they are not always able to muster evidence of innocence). Historically, various tyrannical regimes have often been characterised by adopting judicial processes where the onus of proof is on the defendant to prove his/her innocence of an accusation.

  • We also know that individual criminals cause damage to people, but historically, the greater danger has been from organised violence by the State, not the actions of private criminals.

  • In view of these historical lessons, the general consensus has been that it is better to place the onus of proof on the prosecution (with a sufficiently high evidentiary threshold) and thereby reduce false-positives at the expense of more false-negatives. This means a greater danger from individual criminals, but reduces the danger of arbitrary imprisonment by the State.

  • In terms of interpreting the principle, courts do not assume that lack of conviction constitutes proof on innocence, and they do not speak about the presumption of innocence in this way. That is why a criminal defendant is said to be "acquitted" rather than being "found innocent".


To promote the good character of the wrongfully convicted, I interviewed Keir Stahlsmith, who said, "you won't even believe the story I have. It's so bizarre, that it strikes me as the truth being stranger than fiction." His case is one that sheds light on how a criminal thinks, and how the innocent can be, and sometimes are even framed for a crime.

A great example of this, is how a USAF Honorably discharged combat veteran of war, with an excellent academic record, a 4.0 aerospace student who never even had as much as a detention in his life, and ended up taking a plea deal after unscrupulous interrogation techniques, and inability to obtain legal resources from inside prison walls. As he waited for answers, the system left him with not even a toothbrush or toilet paper at one point, accusing him of "trying to kill himself" as Corrections Officer Barret said, for using toilet paper to make an eyemask to help him sleep, in a cell where the light was on 24/7. His fear of "returning to such a dehumanizing environment is worse than death" was what kept him from focusing on more important things, such as obtaining legal counsel. They had taken away his toilet paper, and he said, "this was all due to my previous cellmate who had exposed himself to a child," was written up for slamming the door and shouting repeatedly, while Stahlsmith was also punished as a result of this bad company.

Keir Stahlsmith said, "I had to survive in harsh conditions that are more suitable for those already found guilty." He laughed it off, and maintained his innocence, as the system continued to let him down—from misleading him, to signing away his right to a preliminary hearing, to being denied access to resources to build a proper defense—not even having access to a working phone. He caved in saying, "I just wanted to do anything to avoid that place of unethical mistreatment of human beings. It's beyond words how bad it really is inside those walls. I understand that is where criminals go, but I'm not a criminal and never was and never will be. I just want to be a voice for all those who are ever forced to take a plea, because they think it's better than the pressures of the alternative."

Here is an example of just how corrupt the criminal justice system can be. In order for Keir Stahlsmith, resident of Erie, PA, to avoid a more severe penalty—a law-abiding and intelligent citizen with a spotless record—he was wrongfully convicted, reporting he had "no choice" but to give a false confession. This is a combination of both coercion and intimidation, just to avoid jail time. The techniques used by law enforcement and prosecutors, barely even allowed time for him to build any kind of defense, and he said "I was left sitting there with a 30 second interview before the sentencing hearing and that was it." Keir Stahlsmith asked his public defender, "can I plead no contest?"

And as the judge entered, he replied whispering, "then this deal won't work." And he reported that was the only chance he had to go over anything with the hastily appointed defense. Keir never had an opportunity to even obtain a paid attorney, or have answered phone calls from his defense, nor a chance to go over the discovery of evidence, and he wasn't sure what to do, so he just "took the deal" in fear of suffering more punitive damages. He went from prison, to rehab, to a flop house (a very poorly managed recovery house) all just to avoid more time in prison. "This..." he shook his head, stating, "seemed like the most intelligent thing to do, to just go along with it, and be cooperative. I regret it now. Being cooperative doesn't help an innocent person at all, and it's the innocent who want to cooperate!" Keir stated, "See, this is exactly what I thought I went overseas to fight for and protect, and here I am being stripped of all my rights as a human being, in the most undignified manner, and not even a clue of what else to do."

When I asked about the details surrounding his case, he sounded vexed saying, "it was just too complicated, and I've made mistakes as well. So I figured I would just accept the prosecutor's side as long as it kept me out of that hellhole. I was at a loss, and was so shell-shocked from what I had just been through. I felt nothing better could come of it, and the lie would win out in the end. So why bother fighting against such a beast?"

Keir Stahlsmith, who was accused of burning a vending machine inside his old high school, said, "Never in a million years would I do something that stupid and pointless. Besides, I loved that school! Truth is, I simply didn't have a good alibi that anyone could verify, and my situation got complicated because I was pressured into confessing to something I knew was a set up from the start. Someone had threatened to blackmail me, and was out to get revenge. They somehow did a great job of setting me up. I'm just glad it wasn't worse, since they broke in to my house while I was locked up, and they very well could have killed me."

When I investigated further, he gave his account, saying, "Look, I had enemies. I was at an all time low in my life with an unwanted dirty divorce, abd made some poor friends. I was dealing with some really violent and shady characters at that time, and a few of them said they were going to 'completely ruin me' and they almost did."

Weeks prior to the event, he reported vandalism to his home, reported to the police several attempted break-ins, then while locked up, someone successfully did break in and stole and damaged his property. "Now, that's the one who had it out for me. All because he thought my ex-fiancée had drugs stashed somewhere. This guy tried to set me up for check fraud, after obtaining banking documents from my glove compartment."

I understood, Stahlsmith couldn't believe he was set up, and didn't have anything to do with this, and he figured it was easier to "take the deal" not knowing what else to do.

"I just caved in and took the blame. I couldn't even describe how this could happen. I just counted my loss and said I would rather live than let this escalate. It was either take the deal, or basically suicide. I was convinced that I wasn't going to be able to prove anything wild to the contrary, because it seemed too far fetched, and I didn't have time to even put all the pieces of the puzzle together. I figured it sounded more ridiculous to tell the whole truth and when under pressure, I just caved in and took the deal. It was easier for me to just take the bullet, because this guy I suspected was a criminal with a warrant already out for his arrest, for burglary, a heroin addict, and a thief, and why I was even associated with him, was beyond me. I knew that. I knew he was bad news. But my ex-fiancée had problems, too, and I think he believed he would find drugs in my house. One time while partying, this guy demanded someone give him drugs, or else, and he threw a fit. I told him to leave, before things escalated, and the next thing I know, my fiancée turns out to be cheating on me, doing heroin, and my house is broken in to, and I'm taken to jail!"

The truth is sometimes more complicated than the court system is even willing to investigate. "The guy who did that, is criminally insane. Now I'm paying the price."

He maintained his innocence and said, "I was totally framed by someone who had it out for me. And he broke in to my house while I was already a victim of his handiwork. He'll end up in prison eventually, that I'm sure. But I never had a voice. Never had a chance to even tell my side of the story. And that is what I am bothered by most in the justice system. I'm just going to do what is required of me and move on."

I asked him, would he let me publish his story, and he said, "I don't see how that will make a difference, but sure." There are two sides to every story, and this one I felt should have a voice. He thanked me after the interview, was very polite and kind, and well-mannered.

Wrongful conviction happens a lot more than people know, because it's how the justice system is designed, and making it easier for someone like Keir Stahlsmith, to "just take the plea" to avoid possible worse sentencing, and an uphill battle that costs a lot of time and even more money.


In practice, it means that the onus is on the prosecutor to prove the accused is guilty beyond a reasonable doubt. The onus is NOT on the accused to prove him/herself innocent. With only a few exceptions, the accused is not strictly required to provide any evidence. Disclaimer: I am not a lawyer


We are free people. Why are we free ? Because we have not committed any crime. And what do you call a person who has not committed any crime ? Innocent. Therefore by default we are all innocent unless proven otherwise.


Rather, the statement should be "neither innocent nor guilty, until proven to be either innocent or guilty".

No, after a person has committed a crime the person is definitely guilty immediately. And if the person did not commit the crime, it is innocent immediately.

So your suggestion is not an improvement. An improvement could be:

'Presumed innocent, but suspected of crime thus potentially actually guilty, until proven guilty or failure to prove guilt'. But that's too long to become a catchphrase.

From Wikipedia:

"Presumption of innocence" serves to emphasize that [...] and that the accused bears no burden of proof. This is often expressed in the phrase innocent until proven guilty, coined by the English lawyer Sir William Garrow (1760–1840).

The presumption of innocence was originally expressed by the French cardinal and jurist Jean Lemoine in the phrase "item quilbet presumitur innocens nisi probetur nocens (a person is presumed innocent until proven guilty)",


A person is either innocent or guilty. Whether there is proof or not doesn't make a difference to their innocence or guilt. What "innocent until proven guilty" is about is how we should treat the person, and how we should go about to decide whether we believe they are innocent or guilty.

In court, "innocent until proven guilty" means that when someone is accused in court, we start with zero knowledge of his guilt. Being in court isn't evidence of his guilt. Then witnesses come up one after the other, or the accused makes a statement, and as we gather information, the accused eventually may be proven guilty. If we don't hear enough evidence for the guilt, the accused isn't proven guilty.

The other important thing is what statement the court should make at the end of a court case. "Guilty" is one possible statement. What other results should there be? There might be "proven innocent" which might happen if the accused proves that he couldn't have done it. "No grounds for prosecution" might happen if the evidence is all shown irrelevant - most people could never prove they are innocent, but there may be just no reason to believe that they are guilty (any more than reason to believe that a million other people would be guilty). But then we might have a little evicende, or a lot of evidence, or an awful lot but not quite enough evidence. Should we send someone home with a statement "there was a lot of evidence, but not quite enough"? That would be very unfair if the person was innocent; the reason for "lot of evidence" might be coincidence, and the reason for "not quite enough" evidence might be that the person was innocent. So the rule is: You come out of court either guilty, or not guilty = innocent. (In Scotland there is also "not proven", which many think is a bad idea and others think is a good idea).

Your statement "we can confidently assert that a person is innocent, until prove of their guilt emerges" is quite wrong. Of course you can "confidently assert" but that doesn't mean you are right. Lots of people confidently assert lots of things and are wrong. We're not in court. We can have opinions. We take the risk that our opinions are wrong. We either take the risk of treating an innocent person badly, or the risk of being hurt by a guilty person.

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