I have never been on a jury, so this is just a hypothetical…
I have taken university level statistics and research classes in the past, so I have more knowledge of statistics than the average person, but when thinking about how I personally interpret the concept of “reasonable doubt”, percentages don’t really come into it.
I don’t think that if I were on a jury I would decide that I think it’s “97% likely” that the defendant did it, and reasonable=95% therefore I should vote to convict. First of all, those numbers are clearly just pulled out of nowhere, and I don’t think determining guilt and punishing people should be based on a rectal pull. Also, it would be exceedingly unlikely that there would be a case with enough concrete numbers to determine a percent likelihood of guilt that everyone would agree on, and every individual juror might assign a different number to “reasonable”.
Personally, how I interpret “reasonable doubt” is whether a reasonable person could disagree, or whether it would be “unreasonable” to vote for acquittal. If most of the jurors vote guilty, and some vote not guilty - what are their reasons for voting not guilty? When they explain their opinion and what evidence they felt to be persuasive, do they seem reasonable? Basically, I think that “reasonable doubt” means that if a person can make a reasonable argument for acquittal, then the defendant should be found not guilty.
And I think that “it’s a feature, not a bug” that the concept of reasonable doubt is vague. If there’s anywhere that individual judgment and case-by-case deliberation and discussion should occur, it’s in a jury room.
Going back to Cliffy’s point from long ago, another way of phrasing your question is, “who decides what’s reasonable, the juror or someone else?” The system assigns the decision to the juror deliberately.
Chronos.
“there is an x% chance that the semen came from the suspect…… Should the members of the jury vote to convict or not?”
Semantically speaking there is equivocation and ambiguity in your example, therefore, further articulation would be very helpful .Less I misinterpret your position.
Thanks.
Your Conscience: you need nothing more to find what reasonable doubt is!
you cannot quantify this inner light, nothing is more accurate in finding the answer we seek.
There really needs to be an answer to this question, because a case really can come down to hard probabilities, even if they don’t always.
Example: Suppose we have a rape case. The jury is completely satisfied by the evidence that the sex was non-consensual. The prosecution calls as an expert witness a geneticist who tested the semen and the suspect, and says that based on the mathematical analysis he performed, there is an x% chance that the semen came from the suspect. The jury accepts that the geneticist is honest and has performed his tests and analysis correctly. Should the members of the jury vote to convict or not?
“There really needs to be an answer to this question”
Are you saying that any answer is invalid or dubious if not equated by calculus?
Or do you accept other methods of evaluation, in which case the law gives you the answer to your example?
Or do you require both grammatical explanation and mathematical calculation of R.D regardless of the “fact” that one is imperfect, but the other is surely a complete myth? Guess which one is which?
I do not understand why you “seem” to believe that numerically quantifying R.D would in any way shape or form, help. It would “seem” that it is this premise that you build on. May I ask you to cite your research materiel for arriving at the conclusion that;
1.The juries burden could benefit from a percentage figure put on reasonable doubt?
2.Any mental decision making process can be mathematically equated and evaluated?
I apologise for coming across rudely, I suspect that you have grave concerns about injustice and I respect you for that. I just want to point out the law is right to make no attempt to alter its present stance. The laws stance (may not be perfect) but it would seem the best available in the real world.
Any reply will no doubt clarify your position.
Let’s just say that there is 99.999% chance of a match.
Speaking for myself, that alone would not be sufficient. I would require other evidence to back it up. For a start I could never be certain that the test and analysis was done correctly. There is always the possibility of error. Then there are more than 100,000 people in the world. There could be a lot of other people with matching DNA. This ias reasonable doubt, in my mind. But if there’s other evidence against him, e.g. fingerprints, witness identification, incriminating statements during questioning, then the doubt is eliminated.
O.K. I think your point is that the law should “benchmark” a figure in percentage terms on reasonable doubt? I further surmise that your reason for this is that you feel the law has a duty to clarify the opaque nature “opaque by definition “of the law, to clarify in simplistic mathematical terms, thereby resolving some confusion amongst jurists as to what precisely constitutes R.D.
Is that your position Chronos?
Peter Morris
I like you’re thinking Pete.
You refuse to take evidence on face value; you rightly want to test it. You are not going to fall into the trap of assumption because the source of evidence happens to wear a white coat. (So he couldn’t be wrong, could he?)The Barry George trial comes to mind when the expert testimony was relied upon in the original trial. That a single particle of gunpowder found in Georges jacket pocket was evaluated by the presiding judge in his address to the jury as very significant evidence? This so called evidence was rebutted by other experts, opening the door to a retrial. I make the distinction here that legal impropriety was to blame, not the jury.
BYRON WHITE (1975): The purpose of a jury is to guard against the exercise of arbitrary power–to make available the common sense judgement of the community as a hedge against the overzealous or mistaken prosecutor and in preference to the professional or perhaps over conditioned or biased response of a judge.
It assumes more than just rationality.
The common-sense, obvious idea that at some point in the brain, the results of all processing is centralized, given some sort of score, and a decision is made based on that scoring is not well supported. Even within the set of wholly conscious decisions it is rather more complex than that.
I’m happy to elaborate on this but it would take us a little off-topic.
Also, while clearly more money is more desirable, attaching a fixed utility to cash can give misleading results.
We often hoard money and wait to find the most bang for our buck, which means, for example, we might make a transaction that we refused a moment ago. This kind of thing doesn’t fit trivially into models where money has a simple, fixed utility.
To the people saying 95% or 96% certainty is beyond a reasonable doubt, are you comfortable sending an innocent person to prison roughly 4-5% of the time?
I turn on the radio to listen to some new tunes. I like some of them. Later that afternoon, you ask me, “What percentage of pleasant listenability causes you to decide that you ‘like’ a song? 85%? 90%? 95%?”
I look at you like this:
What is gained by translating a gut-level impression into numerical values? I would not have been thinking in those terms.
I get called up for jury duty and get seated on the jury for criminal court. I listen to the arguments presented by the prosecution. The combination of evidence and interpretation and related rhetoric is to some extent convincing although I try to suspend that enough to consider the counterarguments presented by the defense. You ask me “What percentage probability is ‘beyond a reasonable doubt’ as far as you’re concerned?” Again I go because again it’s a gut-level impression. I would not have been trying, in my head, to convert it to some numerical expression. I would not have been thinking in those terms.
Is it somehow right or wrong to do so? Presumably some people do, since the OP’s question implies the OP would think in such terms. An important distinction needs to be made (and has been made several times in this thread but I’ll do so again): there are things that can be narrowly defined and then measured (an example given above is the likelihood of a given DNA sample being from a specified individual if that individual’s DNA is identical in this, that, and this other measurement); and there are things where expressing ‘certainty’ as a number is not a measurement in that sense but just an expression of a gut feeling in numerical nomenclature (“please tell us how sure you feel that the sex was nonconsensual, on a scale of 1 to 10…”). In the latter situation, expressing it as a number in no way generates a more precise evaluation. We live in a world that values quantitative expression, one in which we may share the illusion that “I’m 90% certain” conveys more information than “I am very sure of it”… but it doesn’t.
As geneticist I can tell you that is not how it works.
In simplistic terms, suppose I am testing only for blood type. A sample is recovered from the crime scene. It is proven to belong to the perpertrator of the crime. It tests as blood type A+. I test the defendants blood type and it is O+. The defendant is absolutely excluded. I am 100% certain the defendant did not deposit the sample.
But if the defendant has blood type A+ as then I cannot exclude him. I then calculate that x% of people also have blood type A+. All I am calculating is the chance that any other random person from the population would also have the same test result.
Where this technique becomes powerful is in testing multiple traits which are independant of one another. In that case the probablity of another person randomly matching all the traits becomes 1/a * 1/b * 1/c … where 1/a is the chance on that one individual trait being matched at random. The result of that multiplication is the 1 in ??? chance that *a random person other than the defendant *would also have the same traits.
What exactly do you take to be the point of disagreement between how you said it works and what Chronos said? I’m not seeing any incompatibility there.
